How do I make MineCraft Maps for my server?

as far as i know you have to build everything by yourself (with friends) you can get unlimited items by just typing in the little server bar: give (your name here) item id( the number of the item) and then the amount you want ( max 64) just type in help or ? in the little server bar to get a list of commands... i dont know how to edit max to put like buildings in it automaticly ive never heard of it search it on youtube if it exists youll find it on youtube