A layup allows you to get to the basket quickly. Also it allows you to get closer to the hoop and get an easier chance of getting points. A layup is mainly used when you get a break away.
Instead of stopping, it allows you to get to the basket in one motion
With a layup, when you approach the hoop, you want to start off with your right foot, and if your left handed everything is opposite. Make sure you pick up the ball while doing a layup
After you take your first step, next you want to take another step with your left foot.this allowing you to move closer to the hoop.
After you take your second step with your left foot, you want to bring up your right foot. This will help you extend and get a better reach to the hoop allowing you to get the ball in.