Ended up making mine 8x4 to fit between 2 windows on the side of the house. I put in a paver base and then built a 2x4 floor with three quarter inch plywood.
I drew everything our first so I knew what to order from HD. I followed the plans basically but used 2x4s in the frame of the walls and back. I just used plywood on the back wall. We also can't get cedar fence planks in south Florida, only 6 ft pine pickets, so I made due.
The roof I had to measure once the frame was up, just to be sure. Also used a 2x6 as the cross brace on the front...wanted to make sure it was strong enough to prevent the doors from pulling in and sagging, since they're bigger.
Tools:. Pocket hole jig is a must. And I did this completely solo, so air nailers were a 100% must. Frame nailer and Brad nailer with various size nails. I still may add angled brace 2x4 across the top interior to hold the square. Shingled the roof and added a little $9 solar powered light bulb, with a little panel wired to the roof. Works well. Still needs sealed and shingles trimmed but I get a lot of compliments on this thing. Turned out very impressive.
Cost of everything.....around $400. Time, doing it solo seriously took like 3 days...probably about 25 hours for everything excluding paver base.