First you will need to log into your control panel, and in the top set of icons choose Mail. On the next screen, choose Forwarders.
Choose Add Forwarder In the first box you will add the name of the forwarding account.
For instance "sales", the domain is autopopulated, if you have more than one domain you will see an option to hit the arrow for a drop down box.
In the last box you will put the email address all domain is being forwarded to. Then after clicking add forwarder this forwarder is valid on your account.
This brings you to a page that tells you the forwarder you added and you can click go back to go to the first forwarder option screen.