You can easily share your finished exports to Google Classroom with a click of a button.
Select the class you want to submit this export for in the popup that appears.
Next, select the assignment you want to submit the export to. Teachers, please note that only assignments with a valid due date will appear here.
Finally, click attach to submit the video for the assignment.
When a student has finished this step, you will see the assignment change from unsubmitted to submitted for that student.