Numerous ways, you can just Google how to drift and find a guide. But basically, to start a drift, you have to get your rear tires loose. The easiest way to do this is by either powering over (throttling excessively while turning, inducing oversteer) or by pulling the e-brake. After you get the rear tires loose, you have to keep them loose by throttling and countersteering. If you countersteer too much, your car will straighten out, and you don't want that. In a perfect drift, the nose of your car is always pointed towards the apex of a turn, so aim for that, and countersteer and throttle accordingly. As you get better, you can practice techniques such as clutch kicking, inertia drifting, dirt boosting, etc. Also, if you want to drift, I suggest you learn how to heel-toe downshift.