Change someone else's workflow: remap fields, swap the trigger, run it

Why you have to edit it instead of just running it

Templates were built by someone else for their own situation. Once you paste one in, every node on the canvas points at someone else's things — their Google account, their Slack channel, their field names, the trigger time that suited them. Press Execute and it will fail, because you have no access to any of it.

So a template is not "run it as-is", it is "use it as a skeleton". The skeleton has already decided which nodes to use, how they are wired and how the data flows — your job is to swap the parameters on that skeleton for your own:

• Swap the Google Sheet ID for your own sheet;
• Change the Slack channel from #example-channel to #my-team;
• Replace their credentials with ones authorized under your own account;
• Move the trigger type from "every day at 8:00 am" to "run when someone submits the form".

This chapter walks the whole path once: change parameters, remap fields, add a branch, swap the trigger. It is a hands-on chapter, so follow along the whole way and it will click.

Editing a workflow happens at three levels

Not every change costs the same. Sort what you want to change into levels before you start, and you will not trip over anything.

The sections below follow that order — Level 1 first, then Level 2, and for Level 3 only the most common case, swapping the trigger.

Level 1: change parameter values (using the form-to-Slack template)

Say you have just imported a workflow following Chapter 5, and it looks like this: Google Form Trigger → Slack — someone submits the form and a message lands in Slack. The original author used their Google account, their form and their #general channel. We are going to replace all of it with yours.

1. Open the workflow you imported

   Go back to the Workflows list and click the one you just imported. The canvas opens and you see two nodes with a connection between them. The first node may have a small red dot in its top-left corner, meaning "this node is not configured yet" — that is what you are here to fix.

   

2. Click the first node, Google Form Trigger, and the Parameters panel opens on the right

   Double-click the node (a single click also works) and a large panel opens: input data on the left, Parameters in the middle, output data on the right. The Parameters in the middle are what you edit. No credential is selected yet, so there is a line of red text reading "No credential selected".

3. Swap in your own Google account credential

   Find the Credential to connect with dropdown. Opening it gives you two cases:

   • If you have connected a Google account before (on another workflow, say), you will see your credential listed by name, for example Google API - Elmo. Pick it.
   • If this is your first time, choose + Create new credential. That takes you to the OAuth consent screen, where you sign in to Google and let n8n read and write. Chapter 13 has the full flow.

   Once the credential is chosen, the red text disappears and the fields below it (Form / Trigger On) light up so you can use them.

4. Pick your own Google Form

   The Form field below lists every Google Form under your account. Find the one you want to watch and click it. Leave Trigger On next to it at its default, Form Submitted (it fires whenever someone submits).

5. Click the next node, Slack, and change its credential the same way

   Same move on the Slack node — set Credential to connect with in the Parameters panel on the right to your own Slack workspace account. The first time, it sends you to slack.com to authorize. Come back once you have, and the fields below (Channel / Message) become selectable.

6. Change the channel

   The Channel field takes two approaches: From list picks from a dropdown (recommended — n8n lists every channel you are in), or By ID where you paste a channel ID. Replace the template's #general or #example-channel with the channel you want notified, for example #my-team.

7. Press Save in the top-right corner

   There is a Save button in the top-right of the canvas (or Ctrl+S / Cmd+S). Press it and the bright blue Save button turns grey (some versions also flash a green saved note beside the title) — losing the accent color is what tells you it saved. If you navigate away instead, n8n raises an "unsaved changes" confirmation box; just do not click the wrong button.

Level 1 continued: remap the fields (your first expression)

The Slack node usually has a Message field, and the template author wrote something like this:

New form entry: {{ $json['field1'] }}

Whatever sits inside the two curly braces {{ }} is an Expression — it gets replaced with data handed over by the previous node. $json means "the JSON of the current item", and ['field1'] reads the field called field1.

Here is the problem: the author's Google Form field is called field1, while yours may be called applicant_name. At run time n8n cannot find field1, and Slack posts an awkward "New form entry: undefined". You need the right field name in there.

1. First look at what the previous node outputs

   Go back to the Google Form Trigger node and press Execute step underneath it (that runs this node on its own). It waits for you to submit that form once; when you do, one item of JSON appears in the Output panel on the right. Look at what the fields are actually called — applicant_name, email, vip, for example.

2. Go back to the Slack node and point the expression at the right field

   Click the Slack node and find the Message field. Change {{ $json['field1'] }} to {{ $json['applicant_name'] }}.

3. Let the drag-and-drop hint do the work

   A faster way: move the cursor to the left of the Message field and a small data tree appears (the Input panel on the left) listing every field from the previous node. Drag applicant_name straight into the Message field and n8n fills in {{ $json.applicant_name }} for you — no expression syntax to memorize.

4. Write a message with several fields

   A message can mix several expressions with ordinary text:

   New form submission :bell:
   Name: {{ $json.applicant_name }}
   Email: {{ $json.email }}
   VIP: {{ $json.vip }}

   Write plain text directly, and wrap anything that pulls data in {{ }}.

5. Press Execute step to preview it

   The Slack node can be run on its own too (Execute step) — it takes that Google Form test item as its input and really does post a message to your Slack channel. It has worked when you open Slack and see the message.

Level 2: add a node (a VIP branch)

Your form notification runs now. But your boss has one more requirement: "when a VIP customer submits the form, email the sales manager as well as posting to Slack". That needs one more node and a branch.

The flow you are aiming for:

Google Form Trigger
       ↓
       IF (vip == true?)
       ├─ true  → Gmail (email the manager) → Slack (notify the team)
       └─ false → Slack (notify the team)

1. Insert an IF node between the Google Form node and the Slack node

   Move the cursor onto the connection between Google Form → Slack and a + button appears. Click it, search the nodes panel for "IF" and pick IF (under the Flow category). n8n drops the IF node into the middle of the connection: the Google Form output feeds IF, and one of IF's outputs feeds Slack.

2. Set up the IF condition

   Click the IF node and the Parameters panel shows Conditions. Add one condition:

   • Left side: drag the vip field over from the Input panel on the left (or type {{ $json.vip }} yourself)
   • Middle: choose is equal to
   • Right side: enter true (if the vip field is a boolean) or Yes / Y (if it is text)

   Once that is saved, the IF node has two output dots — true on top, false below.

3. Wire a Gmail node onto the true branch

   Draw a connection out of IF's true output; the nodes panel opens at the far end. Search for "Gmail" and choose Send a message. Set the credential, put the sales manager's email in the recipient field, use a Subject such as VIP customer: {{ $json.applicant_name }}, and write whatever you want in the Body.

4. Wire the original Slack node after the Gmail node

   Draw a connection from the Gmail output to the existing Slack node — that way the VIP branch sends the email first and then posts to Slack.
   Draw a connection from IF's false output to the same Slack node as well — non-VIP submissions only go to Slack. Two connections can land on one node, and n8n runs them in order.

5. Execute manually and test both branches

   Press Execute step on the Google Form Trigger node and submit one piece of fake data with vip=true — you should see the IF node's true branch turn green, Gmail send the mail and Slack post the message. Test again with vip=false — only Slack turns green. You are done when both sides run correctly.

6. Press Save, and do not forget it

   Adding a node needs a Save just as changing a parameter does. It is saved when the Save button in the top right has turned grey and navigating away no longer raises "Unsaved changes".

Level 3 warm-up: change the trigger

The trigger type a template uses will not always suit you. A common case: the template runs on a Schedule Trigger every day at 8:00 am, but you want it to run only when someone presses a button in your front end — for that you need a Webhook Trigger.

1. Delete the existing Schedule Trigger node

   Click the Schedule Trigger node once and press Delete (or right-click and choose Delete). The node disappears, and the connection into it breaks with it. You will restore that in a moment.

2. Add a Webhook Trigger from the nodes panel

   Press the + in the top-left of the canvas (or hit Tab) to open the nodes panel, find Webhook under Trigger, the top category, and drag it onto the spot where Schedule used to sit.

3. Connect the Webhook output to the downstream node

   Draw a connection from the connector dot on the right of the Webhook node to the connector dot on the left of the next node (the one Schedule used to trigger). Once it is connected, the downstream node lights up to say it has an input again.

4. Get the Webhook's Test URL

   Click the Webhook node and the Parameters panel shows two URLs: Test URL (the temporary one, for when you press Execute step inside n8n) and Production URL (the permanent one, live once the workflow is set to Active). Copy the Test URL and hand it to your front-end engineer, or call it with curl to try it.

After swapping the trigger type, go back and Execute the whole workflow manually once to confirm nothing is broken. The next section covers the three checks to run after every edit.

Three checks to run after every edit

After you save the change and before you switch the workflow to Active, do these three things. Skipping them is how you plant a problem for later.

1. Press Save and confirm the Save button turns grey

   Press Save and the blue Save button in the top right turns grey and loses its accent color — that means there are no unsaved changes. If the button is still bright blue, or n8n raises an "Unsaved changes" dialog when you try to navigate away, it did not save. The usual reason is that you were typing in a node field and have not clicked into empty space to commit the value. Click an empty part of the canvas, then press Save.

2. Press Execute Workflow and run the whole thing once by hand

   There is a large Execute Workflow button at the bottom-center of the canvas. Press it and n8n runs the workflow from the top (the trigger either uses fake trigger data or asks you to fire it live). Watch whether every node gets a green border, and whether any node turns red.

3. Open the Executions page and confirm every node has a green check

   The sidebar has Executions (the execution history). The run you just did appears at the top. Click into it for the detail — every node should carry a green ✓ icon. Opening a node with a red ✗ shows you the error message.

Only when all three pass should you flip the Active toggle in the top right and take the workflow live. Once Active is on, a Schedule Trigger runs on its schedule and a Webhook Trigger accepts outside calls.

Common ways people break a workflow

If something feels wrong mid-edit, check this table first — it is usually one of these.

Getting unstuck

1. "I deleted a node by accident"

   Press Ctrl+Z (Cmd+Z on a Mac) to undo — the n8n canvas supports undo/redo, as long as you have not refreshed the page (a refresh clears the undo stack). If you already pressed Save and reloaded, and undo cannot get you back, you need the Workflow History covered below: from the workflow list open the workflow → ⋮ in the top right → Workflow history (on by default in the self-hosted edition; on Cloud the retention days depend on the plan). From there you can see past versions and restore one.

2. "I pressed Save but reopening shows nothing was saved"

   A Save only counts once the button turns grey — if it is still bright blue, there is an uncommitted field edit. Click an empty part of the canvas first to move the cursor out of the field, then press Save, or use the Ctrl+S (Cmd+S on a Mac) shortcut.

3. "I want two versions of one template so I can test both"

   Go back to the Workflows list, find the workflow, and choose Duplicate from the ⋮ (three-dot menu) on the right. That gives you an identical workflow with "copy" appended to the name. Edit the copy however you like and keep the original as your backup.

4. "The Executions panel is all red and I do not know which one to fix first"

   Every row on the Executions page shows which node failed. Start at the top (the most recent failure), click in, read the error message, fix that node's fields, then press Execute Workflow to retry. Fixing one often clears the next by itself. Do not change five things at once — change one, run once, look at the result.

5. "I want to compare before and after"

   n8n has no visual diff tool on the canvas. Workflow History (the self-hosted Community edition has it too, with the environment variable N8N_WORKFLOW_HISTORY_PRUNE_TIME controlling retention; Cloud gives 5 to unlimited days depending on the plan) lets you view two versions side by side and restore one, but it shows which node was changed rather than a word-by-word diff. For a line-by-line comparison, the practical route is to export the workflow as JSON (⋮ → Download), save it, and compare the two JSON files in VS Code. Enterprise Source Control binds the whole instance to Git for pull-request-level review; it is not a diff button for a single workflow.

6. "The Webhook URL stopped working after my edit"

   A Webhook has two URLs, Test and Production. The Test URL is only live while you are in the n8n editor with Execute step / Listen for test event running, and it expires. The Production URL only works once the workflow is switched to Active. Mixing the two up is the most common trap when debugging a Webhook; Chapter 22 has the detail.

FAQ