First of all, you should know that this is the basic trick of all skate tricks and you should focus on learning this first.

As above, you should figure out which you're better at, normal or goofy. Normal is when you have your right foot on the tail, like me. Goofy is when you skate opposite of this (left foot on the tail). Now you put your other foot about halfway up the board, aiming towards the toe edge.

Bend down at the knees and lean forward while keeping your balance.