There are many types of flicks ranging from simple to extremely complex. The ones covered here will be the expert level flicks. At this point you should be comfortable flicking the ball normally.
Usually during a Dribble, you pop the ball then turns your car either 45 or 90 degrees to the left or right in relation to the ball. Then Diagonal-Backflip so that your car scoops the ball and can flick it with the nose of the car.