9- With the 2 locating pieces installed, cut the apron loose along the line. Remove the screws keeping the apron in place. Apron on the floor! That should look like this (note the locating piece in place):
10- I kept the cutouts of the aluminum plates to complete the assembly. I used many, many M8 bolts with 1” flats. As any project of that sort, it’s much overdesigned and can probably support the entire car weight, but, what the heck!