The one-hour setup path

This is the order that avoids waiting. Do step 1 first because DNS takes the longest to show up; everything else runs while it propagates.

1. Sign up at the Applane console with your work account and create the company. 2 minutes. Sign up
2. Add the TXT record the console shows you. 5 minutes. Verify your domain
3. Create the builders group applane-builders@<YOUR_DOMAIN> in the Google Admin console, plus applane-admins@<YOUR_DOMAIN> and the applane-bot@<YOUR_DOMAIN> account. 5 minutes. Accounts and groups
4. Prepare the GCP project. Open in Cloud Shell, or run the script. 10 minutes. Set up the project
5. Consent screen and OAuth client in the Google Cloud console. 5 minutes. OAuth consent screen, OAuth client
6. Allow or force-install the extension in the Google Admin console. 5 minutes. Chrome extension policy
7. Paste the values into the console and run the checker. 5 minutes. Setup checklist
8. Install the extension and sign in yourself. Turn on the Apps Script API when the extension asks. 3 minutes. Install and sign in
9. Build one app. 10 minutes. Your first app

If the DNS record has not propagated by step 8, the extension shows unknown_domain. Wait and try again; nothing else needs redoing. See Error messages.