You will first need to set up an e-mail account via your site's cPanel. The settings for your e-mail account are as shown below.
Incoming mail (POP3) server: mail.yourdomain.com
Outgoing mail (SMTP) server: mail.yourdomain.com
The username is your email address. Please remember that the username is the full e-mail address not just the portion before the @ symbol.
Be sure to set SMTP authorization within your email program to have the server authenticate you as a registered account holder.