Deploy from GitHub
GitHub projects start with a personal access token. Paste it in the form and the panel lists repositories you can deploy, including private ones when the token has the repo scope. A fine-grained token needs Contents read and Administration write so a deploy key can be added.
The token is used for that step and is not saved. Later deploys use a read-only deploy key on the repository. You can search the list, pick a branch, and deploy the latest commit or an older one from the history.
Auto-deploy is on by default for a new GitHub site. When it is on, a push to that branch queues a new deployment. If the hook is not installed yet, the form asks for a token again so it can be added.
The Deployments pane is where you change branch, turn auto-deploy on or off, and ship a commit. Logs for those deployments are on the Logs pane.