E-Mail aliases are essentially forwarders from one mailbox name to another.
You can manage E-Mail via the "E-Mail Domains" option on the left navigation bar of the Dashboard.
Select your domain from the Mail Domains menu.
Then, select the user that the alias should forward to
and go to E-Mail Aliases.
Adding an E-Mail alias
Click Add E-Mail alias and enter the the name of the address you want forwarded to the account you are managing. For instance, you might want all of your social networking E-Mail to go to an alias for easy filtering.
Removing an E-Mail alias
Select the radio button next to the alias to remove and click Remove E-Mail alias.