I just winged mine.
6x6, door on the back, two Deerview windows on the front and a single longer one on each side. Framing was easy, added the roof after I had it assembled in the field.
I framed and skinned it in my garage, then took it apart into 4 sections, loaded it on the trailer and brought it to my lease. Took about half a day to put back together and get everything lined up. Put the windows in after everything else was all done so I didn't accidentally break them.
Roomier is by far better. I took the time to seal it up tight to keep moisture out, put a couple of coats of paint over the OSB skin to seal it up, including making sure I painted every edge with good heavy coverage. Roof is a OSB deck cut to just outside the walls and then corrugated tin screwed to it. Dry as a bone, stays warm when the heater buddy is fired up, and I can stretch out or pack the kiddos in (and still stretch out).