You are building vs. buying one of these? If you can, that is the best way to go.
Amazing to me the commercial builders of these coops ALL seem to know so much about putting together a really nice building, but know so little about chickens. The stated capacity per SF of building and number of nest boxes per bird capacity are dead giveaways. They only know they need to include roosts, next boxes and such, but few if any seem to have any real idea on how to configure them or occur to them that it might matter. I would suspect many will tell you it doesn't. That tells me they don't know or care. They are mostly concerned about building something to sell, not what happens downstream of the purchase.
So, take something like what they have and if you used metal sides and roof, DO include exterior insulation. May not be necessary with wood siding, but should be with metal. Absolutely needed if you use a metal roof.
You only need 1 nest box per 4 or so birds. Some say 5. I have 1 per 3 birds. Nest boxes should be up off the floor at least a foot or so, so they can't peak in from floor level. External boxes like they used are OK, but you need a sturdy latch to secure them from predators. If internal, put a slanted roof above the nest boxes so they can't rest or perch on them and roost bars elevated above the nest boxes. Birds will roost on the highest perch they can, so that needs to be the roost bars. The 2" x 2" roosts they show are fine. Minimum of 24" off the deck and can go as high as 30" to 36" provided they have enough space to land in, using a 45 degree glide path.
These coops need lots of natural ventilation. Opening windows like they have are fine (face them south), but it needs vents too. They probably intended this to be closed up in the cold of winter, which would make it a bad place for a chicken to be.
These guys all seem to be using space requirements of 1.5 to 2 SF per bird, which is the standard for cage free and perhaps free range commercial flocks, but historically, is way over packed. Should be at least 3 SF for bantams and smaller breeds like leghorns and 4 sf for larger layer breeds. So take what they give you as capacity and cut it in half and it may work.