Here below example for 10.4

Example for 10.3 and 10.5

Before starting, to avoid errors while setting up Mail, make sure that you are connected to the Internet. If you cannot be connected to the Internet, you may still set up Mail, but additional steps will be required.

1) In the Dock, click on the Mail icon.

2) If this is the first time you've opened the Mail application, you will immediately be brought to the New Account  setup assistant.

Click the Continue button at the bottom right and skip to step 6 below.

3) If you've opened Mail before, wait for Mail to open then click on the Mail menu at the top left of your screen and select Preferences.

4) Click on the Accounts icon at the top of the window.

5) Click on the plus sign ( + ) at the bottom left of the window, circled in the example below.

6) In the General Information area, set the Account Type to "POP."

        a) Enter "Main Account" (or a description of your choosing) for the Account Description.

        b) Enter your name in the Full Name field.

        c) Enter your e-mail address in the Email Address field.The window should now look like the example below.

        d) Click the Continue button.

7) In the Incoming Mail Server area

        a) Enter "mail.yourdomain.com", substituting"yourdomain.com" with your actual domain name into the Incoming Mail Server field. ( ex: mail.wcpdemo.com)

        b) Enter your username into the User Name field

        c) Enter your password in the Password field.The window should look like the example below.

Note: If you get an error like the example below, this either means you are not connected to the Internet or that your e-mail username or password are incorrect. Try retyping both of them making sure the "Caps Lock" key on your keyboard is not on.

Click the Continue button and go on to step 8.

8) In the Outgoing Mail Server area, enter "smtp.yourdomain.com" in the Outgoing Mail Server field. (ex: smtp.wcpdemo.com)

Check with your specific ISP for exact Outgoing server settings

Click the Continue button.