You probably need to take a little time to figure out which direction you are oriented, where the sun is when it is hottest in the afternoon, which way the prevailing wind blows, etc.
Mistakes can be made by blocking off the nice cooling breeze accidentally by the one full wall you may have, or orienting the coop so the winter rains blow in on the roosts. So it pays to study your back yard and the weather patterns there.
You will want to make sure the bottom of the coop is not easy to tunnel under. Some people place rocks or concrete blocks around the bottom outside of the coop/pen, to keep critters from burrowing or digging under. We did an apron buried for my coop, but I think blocks/boulders would work well, too.
Living in Missouri, we needed to protect the birds from the winter north/west wind, but also allow the summer breeze to blow through. I (sort of) solved this by having the south end of the cage 1/2" hardware cloth. Open all the time. The north end is hardware cloth, but with a same- size door that I close during the winter or a hard rain. The west side has the nest boxes, and the east side has a pop door and a people door.
I have had to modify a little for extreme weather: in deep winter I use plastic to close off about 2/3 of the south screened area. It still lets the light in, but keeps some of the snow out.
In hot weather I have had a window fan sitting at the south side, to help cool the inside.
Now I have electricity to the inside of the coop, so I will hang a small fan inside this summer, I think.
Sorry this is so long, but one more thing that might interest you: We built the coop about 2' off the ground, so the chickens can go under the coop in the shade. Some days they spend the whole day lying around in the cool soil under there. I have a 12'x12' heavy wire fenced area which includes the 4'x8' coop. I have had poultry netting on the top of the run, but we are installing wire this week, hopefully.
