Please follow the steps below:

1. Log into your MyPanel.
2. In the Email Settings tab, click on Main Settings
3. On the Email administration page, click on Add a POP3 email account to [yourdomain]
4. Enter a name for the mailbox in the Address box
5. Enter a password, and then confirm the password
6. Click Add
7. The mailbox should have been added successfully, any errors will be displayed.

Here is a tutorial video of the process: