You can sign-up google adsense and begin for work at www.google.com/adsense when you have sign-up you must wait 1-3 days for google team has check your web sites doesn't false terms and coditions of google. Behind you will receive mail concern your web sites ready to use for setup google adsense now.
You may log in to your account and manage your ads of you , which you can choose it several pattern for display on your ads. Google Adsense to be divide part of earnings is 3 part is adsense for content , adsense for search and adsense for referrals which when you to be setup this part on your web sites and have person interest sign - up adsense from your web sites and your account , when these person can make $100 or more. You will receive earnings $100 same too. And have any part of earnings such as dowload several program in system too.