I started off by setting up the wing level on the bench. Actually, the important part was to make sure the main and rear spars where in alignment at both ends. I used a block of aluminum and some tape to mark the level. Once the wing was level, I rechecked the position of the two spar holes. With everything in alignment I proceeded to fit the bottom skin. The tough part was figuring out just how far in or out to place the wing. Once I completed all of the pilot holes in the bottom skin I used my cargo straps to pull the leading edge skin into place. Next, I started to drill the pilot holes in the leading edge skin. I drilled all of the holes in the leading edge except for the holes that go through the main spar.