In order to change your forwarding settings, log into the account you wish your GUSmail to be forwarded to.
In your preferred email account, click the Settings tab. For gmail users, this is a gear shaped icon on the upper right of the screen; click the icon for mail settings.
Select the Forwarding and POP/IMAP tab. Add a forwarding address, then enable POP email to arrive into your account.
After selecting your forwarding preferences, a confirmation email will be sent to your account. Be sure to make this confirmation in order for forwarding to activate.