You must use Insights to configure this. Insights is available directly here: https://insights.studyo.app or by following the steps below:
Login to https://insights.studyo.app
Use the same login you use for Studyo.
Select "Manage this school" in your profile menu.
Select "External accounts" in the left menu
Click The Google Classroom icon in the top right and click Authorize with Google
Click on the View Associations icon and select the correct Classrooms to pull classwork from.
Don’t forget to Save.