Pine gives a main menu of commands when you open it (after the introductory screen the first time you open it), and also a list of other common commands at the bottom (there are many, just type o to get more. To set up Pine, type s for setup, and then c for config.
The configuration can be done much in the same way that you do it for Mail.app. If you have sendmail set up on your computer (to find out how to do that, do a search here for "sendmail"), then you can enter in "127.0.0.1" for smtp-server. Otherwise, enter in what you would normally use for this.