I've built two Arestis and I had trouble the first time I tried to mount the wheel pants because the directions have a few flaws. As for the plywood, the pants that came with my kit already had the plywood installed on one side of each pant but the directions still mentioned that I needed to add the plywood. When you drill the hole for the spindle you may need to lower it by an 1/8". The directions say to measure up 5/8" but my tires rubbed, which wasn't fun to fix, so I measured 1/2" up the second time and that was perfect. The hole you drill for the spindle needs to be big enough for the entire spindle to fit through. I made mine fit perfectly to the hex on the spindle. The 4-40 screw is the only thing that mounts the pant to the landing gear. The spindle keeps it from spinning. Both of my kits came with landing gear that have two holes. Weird yours didn't.