"How do I make money with affiliate programs" is too big of a question to answer with too many variables and the answer is "it depends".
It's kind of like going to a construction forum and asking "How do I build a house?" The answer is it depends on what kind of house - but then too there are so many different stages of building a house it's hard to explain it all in one sweeping post.
There are SO many different ways to get started with affiliate marketing and there is no BEST way or everyone would be doing it and it would no longer work. So the best way to start, in part depends on you! Do you have any site building skills? Any marketing or advertising background? Have you done other kinds of online marketing?
None of the above are necessary, but could help guide us to give you more specific answers.
If I were you, I'd read up a little more on the basics of affiliate marketing and then try to give us some info on your background and ask more specific questions about how to get started if you can.
Here's a basic overview of how it works.
http://en.wikipedia.org/wiki/Affiliate_marketing
Hope this helps and best of luck!