First of all, you need to have a Google Adsense account from Google. Google Adsense can open from that link. But their process is unique. It is hard be a Google Adsense account. You need a pro websites or blogs for it.
For example, you are open a blog for first time and write some text in it. If your blog don't have 20 text in it, please don't subscribe Google Adsense. You can rejected easy. But if you are write some text on good niches. You can accepted by Google Adsense program.
Time of acceptance, you can add ads to your site and other sites which you want. It is too common to use Google Adsense in knowledge blogs. With this action you can get money from program. In turkey and other eastern countries you can get pay 10 cents for clicks. But if you write quality text for European countries or United States. You can get 1$ or more dollars for every click.
This is your recipe,
1- Open your blog or websites.
2- Adding more than 20 text.
3- Register google account and after google adsense.
4- Wait for email (it comes in a week)
5- After acceptance, add your advertisement.