Note that the directions are referring to the wrong steps. It should read "Step 20 through 23". I also waited to remove the leading edge skins for trimming until this step or else you remove them twice....once for the Upper Skins and second for the LWR skins. If you wait until this step it saves time! This is the step where I also remove all the protective cover from over the rivet lines. It makes it less messy when drilling and you can see the hole better.