I don't understand the first question, but the second, "how to get benefit from CPA company" that's easy, get people to fill out there offers and you make great money, if you do it right.
I guess your looking to advertise other people's products or services ... In that case, join an Affiliate Network ... Otherwise, as a Website owner, you are the advertiser ... or ... You are a Publisher, when joining an Affilate Network ... or ... You are an Advertiser, if you use PPC marketing ... .. LOL ... Hope this Helps ! ! !