Create a Personal Access Token with the following properties:
Name: For your team's internal use. No functionality is associated with this property.
Expiration: *** Leave blank.
Scopes: The api, read_user, and read_repository scopes should all be checked.
Once generated, copy the personal access token to your clipboard and go back to the PullRequest Proxy UI with the GitLab Settings modal open.
Add Posting User to Proxy
Enter PullRequest as the PullRequest Username (or whatever name was used in GitLab).
Make sure the PullRequest Username is spelled exactly as the username of the PullRequest user that was created. We highly recommend "PullRequest" (all one word, PascalCase) to maintain communication consistency.
Add Personal Access Token to Proxy
Paste the Personal Access Token into the modal and click Update.
Open the Repositories tab in the left sidebar. The repositories the PullRequest GitLab user were added to should appear in a list here.