After mounting your network drive, you can put files on your H:-drive and remove files from it.
To check your quota select all folders and/or files. Then right click and select "Properties". A calculation will be made.
Athena uses the H:-drive to store data from a number of applications.
On Athena, by going to Standard - Home Drive, you can check what folders are part of your account and how much disk space every folder takes up. If necessary, you can remove folders and/or files.