Creating a forwarder through Webmail
This is the easiest method. Start by logging into your webmail. Remember, you can log into webmail by visiting http://yourdomain.com/webmail (replace yourdomain with the website / subscription domain name). Also be sure to use the full email address as the username and the password associated with the email account you are logging into. So, if you want to forward for susie@yourdomain...login as susie @ yourdomain...
Now, verify you are logged into the correct email address in the upper right and click "Forwarders"
"This screen shows you currently have no forwarders set up" and it should be empty. Click the "Add Forwarder" button.
Fill in the field with the address to forward to and click "add forwarder".