Step 1: Connect the repository
Install the Cretask GitHub app and grant it access to the repositories you want linked. Repository-level access is deliberate, you are not asked for the whole organisation. Cretask stores the installation, not your personal token, so the link survives when someone leaves the team.
Step 2: Reference tasks from commits
Mention a task key in a branch name, a commit message or a pull request title and Cretask links them automatically. The task detail then shows the branch, the open pull request and its review state, so a status question is answered by looking rather than asking.
Step 3: Move tasks on merge
Choose what a merged pull request should do: move the linked task to a status you pick, leave a comment with the merge commit, or both. Draft pull requests can move a task into In Progress. Nothing moves silently, every automated transition is recorded with the pull request that caused it.
Step 4: Keep the two directions honest
If a pull request is closed without merging, the task is not marked done, it is flagged so somebody looks at it. Deleted branches unlink cleanly. The integration is deliberately conservative, because a task board that lies is worse than no board.