Expression used to tell someone that he isn't doing something right, he did a mistake or he just can't understand how to do it.
Like in a game where you can learn the game mechanics and turn them in your favor, sometimes in rl you can exploit something using a tenth of the others' energy.
In a subway, your friends are oblitering the ticket. Suddenly you pop out at the other side without using your ticket.
Genna: "OMG Fanu how did you do that?"
Fanu: "Learn the game mechanics, noob."