Driver's side mount, uses existing holes in the frame.
And same mount viewed from the winch side.
You can see the intended holes for the left two bolts. I dropped the bumper about 1.5" so it would tuck under the plastic trim below my grille. I'm pretty sure this was for a '99-2002 truck, which would not have had the black spacer band under the grill.
The right two bolts are toward the front of the bumper, and were both drilled through, the upper one from the outside using the original hole in the bracket, and the lower from the inside using the original hole in the bumper. That gives me four bolts on each side instead of ARB's intended three bolts... Probably not necessary, but didn't take me long, and I like to overkill things when I can.
I also put the factory tow hooks back in place, and found longer bolts for the outboard bolt in each hook, which also now goes through the bumper mounting plate. My bumper didn't come with the giant tow eyes that ARB uses, so my tow hooks are needed. They're plenty accessible, and far easier to use than an eye. I looked into buying eyes at one time, but they're expensive... No need.