Classroom Folder Structure In Google Drive
The first thing that is important to understand is that Google Classroom automatically generates a folder structure on Google Drive for Classroom to use. All documents used by you and your students in Google Classroom will be stored somewhere in the Classroom folder on your Drive. Do not attempt to delete or change this folder structure! Doing so can cause glitches in Classroom and Drive.
Inside the Classroom folder, a subfolder is generated for each separate classroom you create. Inside the subfolder for each Classroom, you'll find subfolders for each and every assignment you post in Google Classroom. The image below shows the structure visually. Instead of "Classroom 1" and "Assignment 1", you'll see folder names that match your Classroom and assignment names.
The Classroom folder on the teacher's Drive contains all the files of all the students. Do not share the Classroom folder with students- this will allow them to see other students' work and constitutes a breach of student privacy. The Classroom folder on the student's Drive contains only the files he or she owns and has worked on.
When you create an assignment and make a copy for every student, the copies are generated the moment you click "assign" and post the assignment to the stream. At this time, the students become the "owner" of their copy and you have viewing rights.
Once students have edited their copy of the document and clicked "turned in" ownership is transferred to the teacher, and student rights are changed to "view only". If the student unsubmits the assignment, ownership will transfer back to the student. When a teacher returns an assignment, the ownership also reverts back to the student.
If you make comments on a submitted document, the student will not be able to see the comments you've made until you return the document, or the student unsubmits the document.
Unsubmitting and Returning Work
It's important to know that students can unsubmit work at any time. Work can be unsubmitted, resubmitted, and returned to the student as many times as necessary for your purposes (for example, writing revisions). Google Classroom and the document activity stream on Drive will show you when these changes in ownership take place, allowing you to see the timeline of activity if needed.
I hope this answers any questions you may have had about the Google Classroom workflow.