You have received a secret key from CodiumAI to use with the hosted PR-Agent service, store it securely. Acquire a GitLab token with "api" scope and store it safely as well. Register these tokens with CodiumAI to associate your account with your repositories. Install a webhook in your repository or group settings with specific fields filled out, including the URL, secret token, trigger options, and SSL verification. Once set up, you can use PR-Agent's commands in merge requests or comments to automate tasks.