Pre-reqs: You have downloaded and added your child's credentials to both the Google Drive app and the Google Classroom app.
This tutorial on a mobile phone covers how to
- check that you're in the correct Google Drive
- create a document in Google Drive
- star a file in Google Drive
- go to assignments quickly in Google Classroom
- attach anything to an assignment
- attach a Google Drive document in an assignment, either from recent, starred, or all in Google Drive