On your dashboard, you’ll find a form for adding your credentials:
Add an GCP integration. This parameter will also be available as an environment variable.
You are encouraged to use different service accounts for different environments, although they can be shared.
Credentials are created through GCP directly. You’ll want to make a new service key for Chalk with the permissions you require. Credentials are created through GCP’s dashboard. You can create a key and download it from your console here.