This tutorial assumes you have already set up an e-mail account in your control panel.
control panel email account

1) Click File... then click Add Account.
add email account

2) Type your name here as you want it to appear on outgoing mail... your full e-mail address... then enter the password associated with this e-mail address.
enter password

3) Click Continue.
click continue

4) Since we are setting up a mailbox using POP, leave that option selected. Then type a description for this incoming mail server.
pop selected

5) Enter the Incoming Mail Server as provided by your host. Note that this can be anything from to just the domain name as shown here. Then type your username, and click Continue.
incoming mail server

6) In order to send mail from this address, we need to set up the Outgoing Mail Server. Enter a description, followed by the Outgoing Mail Server.
outgoing mail server

7) If required by your host, check Use Authentication... anf then click Continue.
smtp authentication ticked

8) Review the information and click Create.
review information

9) That's it! The mailbox we just set up is shown here, along with all the messages on the server in this account.
mail messages