I use a PC, my wife uses a Mac. Can I set up a share for her also without messing anything up? Or is it an either/or situation? Thanks. 

were a mixed os household here to.  You can setup a a common share with user/group permissions for users regardless of OS.  

This works because the EX4 is it’s OWN computer/OS and manages the files on it’s own filesystem regardless of what the client is PC/Mac/*NIX 

Great, thank you.