Click "Sign in with DBID" below and you'll be taken to another page. On this page, either sign in with an existing DBID account for that environment, or create a new one.
Note, if this account is NOT an admin account and you're trying to access admin content, you'll need to have it made one for this environment; speak with Platform, or check with the CS Tools slack channel.
You'll be able to tell if it isn't an admin account by the errors showing up instead of a proper web page.