Hello

How does the Refer-a-Friend works?

i have refers my sister like 48 hours a go but still haven't got any gold on my account?

am i doing something wrong?
how long does it take?
how much money do you get?
how many many friedns can i refer to/is there a limit?
Do i get money everytime one of my friends refer back to me?
i have like 12 friends on facebook, will i get money?