I am no carpenter either, my coop which was supposed to be 8'x7' came out 8'1"x6'10"x8'2"x7'1" so it is more than a little "off", but then so am I.
I sunk four 4x4 posts in the ground and wrapped it in a combo of plywood and hardware cloth. I topped it off with 2x4 straight rafters and tin for a roof. I used a 4' stair riser with 1x6 steps nailed to it for a ladder to the roost. It took me a couple of months working on Saturdays. It has a dirt floor and the girls like that. My spring project will be to add a run, once again a study on how to saw the boards all wrong. Study the coop section, take a deep breath and jump in. Have fun with it.