If you don't see an entry under mail, click Add, then Mail. You should now be on the general tab. Type in a name like Work or Home for this email account. Organization is optional. Type in your email address.
Reply address is optional.
Click OK at the bottom. Click on the Servers tab. Type the mail server name in the Incoming and Outgoing mail fields. Click on the Connection tab. Make sure you click on the dot next to Connect using a third party dialer.