Just distilling some of what's been written so far . . . It'll depend on budget, experience/skill, and what you want for an end product.
Looking at building from scratch, not a kit (that you seem to have shopped around for . . .)
My big coop, the Pullet Palace, intended as a year-round for my layers . . . tall enough for me to walk around in (5x8 on the bottom , 5' at the back, 7' at the front), wired for lights and a water warmer took several weeks. Sided with shiplap, so a lot of cutting (a chopsaw is a wonderful thing!).
For the meat birds, a large doghouse, 4x8, 2-1/2' at the front, 2' even at the rear with lots of hinges to make for easy access for both feeding and cleaning, it was a healthy day's project. They are a mild weather project, so no wiring involved. Built it as a sled so I can put it anywhere I want. Because I intend top move it on the runners periodically, I used plywood instead of OSB for the sides, so the flexing of the frame doesnt break the screws holding the siding to out so readily.
Something that size and design can be done in a day if you have the materials, tools, and experience. Same design, with any one of those elements missing, figure three or four days.
Chicken rule #1 -- do not order/buy chicks before the coop is built.
Go for it, and good luck!