Step 1: What You'll need
1 inch PT CDX plywood half sheet
2 lbs 3 inch deck screws
2 lbs 2 inch deck screws
Pocket hole jig (optional)
Drill & bits
Assorted woodworking paraphernalia (clamps, cords, etc)
Most of this stuff I had laying around, the wood came from disassembled garden boxes from our previous residence, so I can not give an accurate board footage used. Fasteners should be chosen for compatibility with PT lumber.
Step 2: Let's start
From these 2x3s we cut;
2 24 inch pieces
2 32 inch pieces
4 30 inch pieces with one end of each beveled at 22.5 degrees. (uprights)
2 44 inch pieces with one long edge of each cut at a 22.5 degree angle and the ends snipped at 45 degrees. (stringers)
2 44 inch pieces
I want to add that proper precautions should be taken when working with PT lumber, use a dust mask when sawing, and wash your hands before eating and drinking.