Once you have 20-30 pages on your site, go to http://adsense. google. com to apply.
When you are accepted, simply copy and paste the provided HTML code into any page that you'd like to show the ads. You can opt to display text ads, image ads, or a combination of both. It's up to you.
You can either display the ads vertically along side the page like Google does or in a banner-like formation horizontally across your pages. You can even customize the colors to match your site's theme.