What I need to do to earn with CPA??

I can tell you you're going to lose money with your first campaigns. might even lose money with your first 50-100 campaigns. theres no basic gudie telling you what offer to promote and how. you'll have to figure it out on your own.

I am still learning myself Achu. Read the guide and then try some of the free methods out. From there if you want to try PPC. 7search seems to be a good intro as you only need $25 to get started, the traffic is also a little slower. If you go for one of the bigger networks and don't align your bid and demographics correctly you could find your money wiped out very quickly.

To echo silverace CPA is not a get rich quick. You are very likely to lose money. I had a good start, but now I am running at a slight loss overall, but as I am learning all the time and tracking that data it still has value to me.

To be very honest I have seen quite a few folk come into here wanting someone to show them how its all done. If you are not the type that can relentlessly pursue info yourself and then quickly filter the valuable stuff from the BS then CPA (with paid traffic) may not be the best area for you to learn in. If you know SEO then leverage that and find a niche related to your sites and then find an offer in your CPA network to promote.

Don't mean sound harsh, if your intent is strong my words won't sway you, but if you don't have money to burn and are not serious, I will be saving you some heartache.