1. Log into the Customer Control Panel with your main account's username and password.
2. Click on the Mail tab at the top.
3. Click on +Add New Mailbox.
4. Click the New Service User button, and click Next.
5. Fill in the Display name. Under Login section, check the Login in existing domain button and type the email address you want to create.
After the "@" symbol from the drop down, select the domain of the email address you want to create.
Either type in the desired password you'd like to have or click the Generate button and have the system generate a password for you.
6. Make sure the E-mail address and domain your creating the email address for is correct. (Make sure you select a domain from the drop down.
Select the check box if you want to Enable Antispam.
7. Confirm all the information of the email address you're creating for the domain you want to create is correct and click Finish.
That's it, you've completed creating your new email account.