You need to be patient. You joined three weeks ago and it takes more time for your hubs to get noticed and for you to become more experienced at making money online.
You can sign up for Amazon as well if you want although that it much harder in the beginning to start earning money. Most peope get their flow of income from Google AdSense going first.
You will start making money when your hubs are regularly being viewed and the more views you have, the more chances you have of getting a click on an ad. When that happens, you make money (but don't click on ads yourself because then you will get banned).