Hey @bram.moreinis -- thanks for posting! To clarify, are you the owner of the file you are trying to move to the Team Folder? If not, you wouldn’t be able to move it to the Team Folder. You’d need to create a duplicate of the file (making yourself the owner of the duplicate) and then move it to the Team Folder. 

Hope this helps!

Thank you! That makes sense.

What is the best way to gather student work (which is in process) into one place for my check-ins, or for collective reference? Is there one (outside my creating something)?

Hey @bram.moreinis -- thanks for the response! The best way would be to have the owner of each document put their check-ins in the Team Folder themselves.