It is the same thing I was talking to you once. It is very simple. If you have a website then you can apply for adsense and if they approve. Then you have to place their code in your site, the code will then display ads. If you visitors clicks on those ads then you will be paid.
You can't click your own ads or they will ban you. Also, you need to have real huge traffic in order to earn good from Adsense else its just little fun online and nothing else.

Well, google has many lawsuites filed against them by advertiser for bogus clicks so google is extra careful about fake clicks and they immediately ban on even doubts now days I think.
They do this simply by tracking your IP. ie. you accessing your account from the IP and then clicking on ads.. they will know it then.

Even too much of clicks from single IP are objectionable.

You can report their site to google

If not now then soon their site will get banned as its bad practice. If not you, not me then someother will report.