To open a GP6 Document from your teacher, your teacher should provide you a link to click (GP6 / Chrome).

However, any user can share any GP6 Document Version with any other user by sending the Version ID. A GP6 Document Version ID looks like this:

26C58A1D81T1F2A4B99A425723AD2A13.

Getting the ID for a GP6 Document Version

1. In GP6, open your Library tab.
   
2. Select the Document (upper window), then the Version (lower window).
   
3. Lock the Version using the Save button (upper left disc icon).
   
4. Use the Version Properties button (hover over the Version in the lower window) to view and copy the Version ID.
   
5. Pass the Version ID to any user with whom you want to share that Version.
   

Opening a GP6 Document Version from the ID

1. in GP6, open your Library tab.
   
2. Paste the Version ID into the field labeled "Other Document ID" and click Load (paste using CTRL+v (Windows) or CMD+v (Mac)).
   
3. If you make any changes to the Document you just loaded, GP6 will automatically create a new Version with you as the owner. This new Version will still be linked to and visible to the Document's original owner.