Go to https://login.meetingroomapp.com/. If you haven’t created your MeetingRoomApp account yet, do so now and then log in.
Click on Calendar Providers on the left.
Click on Connect Google Workspace.
In the dialog box, click on the CONTINUE WITH GOOGLE ACCOUNT button and log in using your new Service Account.
Once you are logged in, click on Allow. This will enable MeetingRoomApp to access your calendar.