Set it up

Step-by-step setup

Work through these steps with the posting workflow still unpublished. The first live post is on the next page.

#Prepare the Google Sheet

Create a Google Sheet, or make a copy of the template you were given.
Name the first tab queue. Row 1, in this order: id, platform, message, image_url, link, scheduled_at, status, post_id, error, posted_at You can import sample-queue.csv. Delete or rewrite sample rows before you go live; keep the header.
Add a tab error_log with time, workflow, execution_id, execution_url, failed_node, error_message (see error-log-header.csv).
If you will use the AI planner, add planner_log: time, posts_created, notes.
Copy the Sheet ID from https://docs.google.com/spreadsheets/d/YOUR_SHEET_ID/edit.
Share the Sheet (Editor) with the Google account you will use in n8n.

sample-queue.csv is the starter queue tab (fictional rows only). After a successful post, Mark Posted fills status, post_id, and posted_at on that row.

id	platform	message	image_url	link	scheduled_at	status
demo-001	facebook	Hello from our demo Page! This post was published automatically from our content queue. #automation			2026-11-11T09:00:00+08:00	approved
demo-002	facebook	New guide: 5 ways to keep your social calendar on track. Read it here:		https://example.com	2026-11-12T10:00:00+08:00	draft
demo-003	facebook	Behind the scenes: our team at work. What would you like to see next?	https://upload.wikimedia.org/wikipedia/commons/a/a9/Example.jpg		2026-11-12T18:00:00+08:00	approved

Select Due Approved Posts would keep demo-001 and demo-003 (both approved and due once scheduled_at is in the past) and skip demo-002 (draft). There is no live Google Sheet screenshot in this kit.

#Connect the Facebook Page in Zernio

The client never creates a Meta developer app.

In your Zernio account, create an API key (shown once) and a profile for this client.
Request a Facebook connect URL, for example GET https://zernio.com/api/v1/connect/facebook?profileId={profileId}&redirect_url=https://your-app/callback. Optional: welcome=true and brandName / logoUrl; scopes=posting if you only need publishing now; handoff=true for a QR code. The link lasts 30 minutes.
The client signs in with Facebook and picks the Page (they must be Admin or Editor). You get back accountId and profileId.
Keep accountId for Config zernio_account_id. Personal profiles cannot post. Meta's consent screen still names the Zernio app.

Official references: Connecting accounts, Create post.

#Import the workflows

n8n → Create workflow → ⋯ → Import from File… → workflows/social-posting-error-handler.json → Save.
Repeat for workflows/social-posting-zernio.json.
Optional: import workflows/social-content-ai-planner.json. These files use placeholders such as YOUR_SHEET_ID and YOUR_CREDENTIAL_ID.
All import inactive. Credential badges are expected until the next step.

Posting workflow canvas — The posting workflow after import, with sticky notes on the canvas.

#Create credentials

#Google Sheets OAuth2 API

n8n Cloud: Sign in with Google. Allow Sheets and Drive.
Self-hosted: In Google Cloud Console enable Google Sheets API and Google Drive API. Configure the OAuth consent screen (add your Google account as a test user if the app is External and in Testing). Create a Web application OAuth client and paste the redirect URI from n8n:

Text

https://YOUR-N8N-DOMAIN/rest/oauth2-credential/callback

Copy it exactly, including https and any port. Then paste Client ID and Secret into n8n and sign in.

Select this credential on Read Content Queue, Lock Row (publishing), Mark Posted, Mark Failed, and Log Error to Sheet.

Credentials list in n8n, including Zernio API and Google Sheets — The n8n credentials list. Select Google Sheets OAuth2 and Header Auth named Zernio API on the matching nodes.

#Header Auth: Zernio API

Credentials → Header Auth, name it Zernio API.
Name: Authorization. Value: Bearer plus your Zernio API key (one space after Bearer).
Select it on Publish via Zernio (and on Zernio Presign if you use the planner).

Never put the Zernio API key in a node, the Sheet, or a screenshot.

#Fill in Config

Open Config on the posting workflow and set:

Field	Example
`client_name`	`Your Business`
`zernio_account_id`	`YOUR_ACCOUNT_ID`
`zernio_profile_id`	`YOUR_PROFILE_ID`
`google_sheet_id`	`YOUR_SHEET_ID`
`queue_sheet_name`	`queue`
`max_posts_per_run`	`5`

On Log Error to Sheet in the error handler, paste the same Sheet ID (that node does not read Config). Keep the tab name error_log.

Config node — Config fields. Live Sheet and Zernio IDs are boxed as YOUR_SHEET_ID, YOUR_ACCOUNT_ID, and YOUR_PROFILE_ID.

#Publish the error handler and link it

Open Social Posting – Error Handler and Publish it. It only runs when another workflow fails; it never posts. On n8n 2.47.3 the Error workflow picker greys out unpublished workflows and ones without an Error Trigger.
Posting workflow → ⋯ → Settings → Error workflow → select it → Save.

The buyer JSON ships with settings.errorWorkflow set to YOUR_ERROR_WORKFLOW_ID. Choosing the published error handler in Settings replaces that placeholder.

When this is done, go to Test and go live for the one-row test post. Leave the posting workflow unpublished until that test succeeds.