I had a hard time figuring out the nailers for the plywood. I was going to use 2x2s but quickly realized you can’t put them end to end; you need to toenail them in. At that early point in construction, I wasn’t good at toenailing and so had to use staggered 2x4s so that I could face nail them in. It took a lot of clamping to get them in level with the top. Later Dee taught me how to kerf and chisel out notches in the joists to lay down a long nailer.