Your Retool app will first need to be registered on GitHub. Create a new OAuth app via the "Developer Settings" section of your account's "Settings" page.
Set the "Authorization callback URL" to be
https://oauth.tryretool.com/oauth/user/oauthcallback. You can also find and copy this URL when you create a new GitHub resource within Retool.
Settings > Developer Settings > OAuth Apps > New OAuth App
Enter the "Settings" section for your GitHub app, where you can find the Client ID and Client Secret keys.
Settings > Developer Settings > OAuth Apps > [your GitHub app]
Create a new resource in Retool, and select "GitHub" as the type. Enter your client ID and secret key, and select the permissions you'd like to authorise from the "Scopes" multi-select dropdown. Click the "Test OAuth integration with your own account" button and authorise the application. Press "Save" when you're done.
Resources > Add > Stripe
You can now select your newly-created GitHub resource from the Resource dropdown when creating queries in your Retool apps. The operations that will work for you will depend on the permissions that you approved when you set up the resource.
You can display the results of GitHub queries as with any other query in Retool. You will have to examine the response to see which part of it you actually want to display. In this case, the data we care about is in
githubQuery.data.response.body rather than just