How to retrieve money made from Zazzle.com?

i just designed a pair of childrens shoes on Keds.com, and it asked if i wanted to sell them on zazzle.com. so i made an account and my item got put on the website.i chose that i wanted to collect 15% of every purchased pair. BUT my question is, once people start buying it..if they even do..HOW do i get the money i make??? if someone could help, that would be great! thanks!