Scroll down the page until you reach the Email section.
Click on the Manage email link.
Click on the Create your email addresses option.
Click on the mail box option.
Enter the email address prefix in the box provided, and then select the domain from the drop down box provided. You can specify the type and package you require the mailbox to be. You will need to enter you password, and you will be shown how secure your password is.
There are then some simple admin settings to configure, and then click either the Save and Exit or the Save and Add Another button.
Your new mailbox will now be created.