Follow this guide on how to create a GitHub App and add the homepage URL and callback URL according to your netlify app.
Homepage URL: https://your-netlify-prefix.netlify.app/
Callback URL: https://your-netlify-prefix.app/callback
For this you can follow this getting started page.
But these three commands should be enough:
npm install netlify-cli -g
netlify login
netlify initAfter this add these env vars to netlify:
Any env var without the prefix VITE will not be available on the client side
GITHUB_CLIENT_SECRET=<githubAppSecret>
VITE_GITHUB_CLIENT_ID=<githubAppId>
VITE_CODERS_INITIAL=<githubCoders> // username1,displayName1|username2,displayName2|...