If you look close at the SOS lip there are dimples in it, that is were you drill your holes.
The side pieces don't have the dimples, so lay your old lip over it to get an idea were the holes are.
The big problem are the screw holes next to the tires, the hole has to be perfect to get the screw in.
The plastic wheel well is held in at this location, and has to go in between the lip and the lower dam.
But the fiberglass is thicker than the plastic lip was,
this makes the screw come up kind of short.
So if its not perfectly lined up it won't go.
Keep your drill holes close to the inside of the lip.
I ended up making the holes allot bigger so you have room to work with.
The screws have big washers on them so the hole does not have to be perfect.
Start installing the screws from the middle and work your way to the edges.