I peeled off all the plastic, because it is just easier to work with. I will just have to be careful not to damage the skin. You won't believe how long it takes to get this plastic off.
I drilled, deburred and dimpled the holes in the one side of the skin and the stiffeners
The holes are already made in the stiffeners and the skin, I just needed to drill two new holes that didn't align up nicely. I probably used the wrong stiffeners in the wrong place