Configuring sendmail is fairly difficult at first, but not so bad once you've got used to how to do it. Have you tried reading some of the documentation on www.sendmail.org
-- in particular the readme
? It's fairly comprehensive. Note that there are a lot of options and different ways of setting mail up, so I can't really help more than this unless you're much more specific about how you want things configured. If you're going for just a simple mail set-up, one of the included configuration files might work for you out of the box.