Creating a new email account for a domain name is done through GigoCP
Log in to GigoCP and click Manage Hosting.
Select Manage on the hosting package you wish to create an email account for.
Select Email Accounts under Email.
Enter the name you want your email account to have and select the domain and click Create Email Account.
Your email account will automatically be assigned a password, but as soon as the account is created you'll be able to change this to anything you wish.
You will have immediate access to your webmail account.