You'd be wise to take jvls1942 up on his offer. My DH and I narrowly escaped homicide building our coop.
ETA: If you have a nearby high school with a wood shop program, you could always talk to the teacher about having the coop built as a project... Or they could probably do the plans for you if you really feel that you need them. Truth be told, I think you could probably get by on an 8x8 without plans. We have ZERO construction experience and got a decks/sheds book from Home Depot. It took all summer, but it turned out nice.