To setup a Zimbra Mailbox, do the following:
- In your client area, go to Services -> My Services and click on the Zimbra service
- If you are using multiple levels of Zimbra service, you may see multiple Zimbra services in the list and you would pick one
- Click on "Email Accounts"
- Click "Add Mailbox"
- Fill out the form, you may skip most fields except for the password and email address field
- Submit the form
NOTE: The username for the mailbox is the full email address