This is figure-it-out-as-you-go construction.
1. Take two 2x4s, 1 nail and 1 hammer.
2. Nail them together, anywhere you want.
3. Grab another 2x4 and another and, with the same hammer, nail the new 2x4 somewhere onto the already nailed 2x4s.
4. Step back and check your work.
5. Repeat steps 3 & 4 over and over until you have what looks like whatever you're trying to build.
6. Cover with OSB.
7. Paint and show your masterpiece to the world.