Looking for suggestions!!

Hi everyone

Well after our first year raising chickens, we are of course addicted and are now planning quite a bit more expansion (him with his meat birds and me with my layers and bantam loveys ) What i need are suggestions for my new coop......i was given a beautiful run, very sturdy and covered with chicken wire, that i am actually planning on turning into a coop. I intend to elevate it up, likely another 3 feet and enclose it , put a solid floor on it, steps and a human door, along with a couple of pop-doors. It is pretty big with the center elevated, total thing right now measures 12'x12', and is 5' high in the center with a gradual slope down to 4' on the sides. How should i ventilate it, and what would be the best layout inside for cleaning, feeding, nest boxes, and egg gathering? I would also like to make a few enclosed cages so i can seperate moms and chicks or possibly a space for a brooder and storage. I do not need a run as i free range.