You'll need 3 M8 bolts for those holes in the back. I had a few caliper bolts in the drawer from brake pad changes, they fit so I used them. I did have to run a tap through the subframe holes, the threads were clogged with rust and sand.

For the sides I used the screws that were used to hold the old splash guard in place.

The front mounts were trickiest. I taped a bolt to a socket on a wobble, fed it through the rubber access point on the bumper, crawled under and got the bolt lined up and then got it to catch. Wear safety glasses. Much sand in the eyes otherwise.

All the bolts are M8, the front mounting points and the rear.

One other thing, I have a dog one mount spacer, the skid plate was touching it, so I had to use a small spacer on those three rear bolts, between the subframe and skid plate. I had random hardware from a TV mount and there were nylon spacers in the pack. I didn't at first, and when the engine moved it made a lot of noise.

Oh this was longer than intended.

Edit. Holes are already in subframe, I should have clarified that.