[Share]-How to open all the XD files of the student?

Hi I'm a professor trying XD in class. I gave the students a simple assignment, but with the exception of 5 files - I can not open their files. I would like to see their entire file not the "shared" file because I want to check semantics, best practices,... 

I select open from computer

I select the file

Nothing happens.

<The Title was renamed by moderator>