1. Go to https://www.google.com/adsense/ and register an account. After Google does some verification, you will receive a small bit of javascript coding to place on your website. The whole setup process is very easy to do.
2. Place the coding on your design pages of the website, and ads will begin to appear when people visit your website. The Ads will be related to the visitors location, the content of your site, or other factors.
3. You will begin to earn money based on a per-click or per-impression basis depending on the ad. Google has not released the formula they use to determine how much you will make based on the visitor clicking an advertisement. Therefore, it is unknown what you will earn for the ads. This has been a point of contention with Google Adsense.
4. Also, please note that Google will only pay you once you earn $100. For most smaller websites, this will take a very long time. However, if you choose to close your Adsense account, Google will pay out to the account holder if they have more than $10.
5. To help maximize profits, some website owners have discovered ways to trick Adsense. Please visit the Wikipedia page for ideas on this: http://en.wikipedia.org/wiki/AdSense