A real, verified walkthrough — every screen, every exact button label, and the specific mistakes worth avoiding. Written by actually doing it, not guessed from memory.
/gsc-callback.html added to the end (e.g. https://yoursite.com/gsc-callback.html).https://yoursite.com). Under "Authorized redirect URIs," click + Add URI and enter the exact address you just confirmed in Step 10. Click the blue Create button.GOOGLE_CLIENT_SECRET), never into the app itself.