This document covers how to save an attachment from campus web mail in the supported browser on campus.
Open the email message. Control-click (right click) on the file name and select "Download Linked File". This will automatically save the file to your "Downloads" folder in your home folder; unless the default download destination as been changed.
Open the email message. Control-click on the file name and select "Open Link in New Tab. Firefox will now prompt for a location to save to. Save the attachment in the desired folder.