Open up Mail.

MacMail01

Click on the ‘File’ menu, and click on ‘Add Account…’

MacMail02

Type in your name (However you’d like it displayed), your full e-mail Address, and password.
Click Continue.

MacMail03

The Account Type should be POP.
Description is an optional label for the email account.
The Incoming Mail Server should be mail.cass.net
Type your username, which is the first part to your email address, and then your password.
Click Continue.

MacMail04

Leave the checkbox unchecked, and Authentication should be ‘Password’. Click Continue.

MacMail05

The Outgoing Mail server should also be mail.cass.net
Make sure ‘Use Authentication’ is checked.
Type your username, which is the first part to your email address, and then your password.
Click Continue.