I wish there was a step by step guide that worked, but the problem is, if there was, everyone would start the same way and it would probably be so competitive it would cease to work for anyone.
One of the beauties of affiliate marketing is it's so diverse and there are so many ways to do it.
That also makes it hard because there is no one BEST way to get started.
Have you read all the stickies in the newbie forum yet? After you do that and read a couple in the niche marketing forum about how to pick your 1st niche, you should start to have some ah-ha moments where the light starts to come on and things start to make sense.
I don't remember if I've mentioned this to you but another source of free training is
Affilorama.
I haven't been through all their stuff, but it's free and seems decent.