Pretty simple - this is my work time stuff
You need a server address for incoming emails and one address for outgoing emails.
the incoming server is most likely a POP3. You download your emails from that and have them on your computer.
Sometimes a IMAP Server is used. Mostly with mobiles. That one presents the header from the email (subject, sender, date, ...), the content is fetched when you read the mail.
For sending emails you'll have to add a SMTP server. That one is responsible for sending emails.
And before I really start to explain:
Dishmail.net - Guide to configuration of Outlook ExpressThat should guide you through the process.