We’ve published our Google Sheets add-on, but new users often don’t know how to access the extension after installing it. Currently, this is what we show by default, but I’m not sure how to change it.

I’ve noticed that some add-ons include an image with instructions like this one. How can I achieve that?

Thanks!

Relevant docs:

• https://developers.google.com/apps-script/manifest
• https://developers.google.com/apps-script/manifest/editor-addons
• https://developers.google.com/workspace/add-ons/concepts/homepages

Gemini suggested a possible solution, but it conflicts with the manifect structure. Adding onInstallation to appsscript.json

{
  "manifestVersion": 2,
  "name": "My Addon",
  "description": "A sample addon that displays a custom message on installation.",
  "developerMetadata": {
    "supportsDomainWideInstallation": false
  },
  "oauthScopes": [
    "https://www.googleapis.com/auth/spreadsheets"
  ],
  "iconUrl": "https://www.example.com/icon.png",
  "onInstallation": {
    "type": "message",
    "message": "Thank you for installing My Addon!nnTo get started, follow these steps:n1. Click on the addon icon in your Sheets sidebar.n2. Select the 'Instructions' tab.n3. Follow the instructions on the page.",
    "image": {
      "url": "https://www.example.com/instructions.png"
    }
  }
}

results in an error: “Invalid manifest, unknown fields: homepageUrl, onInstallation.”