Create Google API key (alternatively use this Google support article)

1. Log in to Google Console
2. Select or create a project
   
3. Enable GoogleSheets API if it's disabled. Wait several minutes after enabling API. ( Google's guide, search for sheets)
   
4. Select Credentials , click on Create credentials and choose API key
   
5. Copy your new API key and paste it to DataSource API Key parameter
   
6. Open up your spreadsheet in your browser, copy the URL, click on Retrieve from URL button, paste the URL and click on Parse button to fill Spreadsheet ID (alternatively read this article to learn how to obtain SpreadsheetID)
   
7. Make sure your spreadsheet is public or accessible with link. Open up your spreadsheet in your browser, click on Share button, then Get sharable link , then Done
   
8. Save settings