Some departmental services are available from off-campus without VPN:

• Stafflogin server Secure shell / SFTP
• Intranet www.dcs.shef.ac.uk/intranet

All other services would require VPN. For instructions on how to set that up go to https://www.sheffield.ac.uk/it-services/vpn

(AKA H-drive)

When on VPN, it can be accessed as if on campus:

\\staffstore.dcs.shef.ac.uk\username (On Windows) 
smb://staffstore.dcs.shef.ac.uk/username'' (On Linux or Mac)

(Change 'username' for your user name!)

When it asks for the domain, put COMSCIAD. On the Windows login, when you enter your username enter it as COMSCIAD\username

More info on how to map to a drive letter on Windows

For Linux users, it can also be mounted using SSHFS. See Access to home dir with sshfs