Each time someone clicks on one of the ads on your blog you will be paid for it. If someone does a search via your blog and clicks on one of those ads you will be paid for those too, and if you refer people to a site you will be paid for that too! Adsense basically allows you to get paid simply for blogging and getting people to read your blog. You may NOT however tell people to click on your ads as that is cheating. They have to do that on their own.
Now to find out how you get paid!