If you need to use either a POP server or IMAP server then you will need to select the server type and then enter in the hostname or IP address of the mail server. If you are not sure where the mail comes to then you can ask someone else who has set up mail on the same machine.
Once you have your incoming mail settings figured out you will need to setup the outgoing settings. If your mail server is on the same machine you can just type in localhost in for the mail server. If the mail server is is separate machine then you will need to type in the hostname or IP address. For the outgoing mail server user name you will again need to put in your login name.