How do i code for maple story private servers, in the making of the private server?

My Friend asked me if i can code for a maple story private server he is making, i told him no, but i can learn really quick, so i need to learn how to code a maple story private server, but i have no i dea where to start, i am addicted to maple story and really want to help my friend, because if he makes it and i code it we will be fine. So please if you know any details please help me. it would be much appreciated.