The front ones it think are obvious, the u clamp with the hollow post clamps to the front bumper, and the end of the guard is placed into it, with the top fixing bracket in place on the top of the guard and touching the slam panel drill two screw holes and fix the bracket with stainless screws & washers to suit.
You will need the small rubber buffers that fit in the holes on the side of the outer edge of the guard, best of luck finding them now, there should be four per guard but I’m only left with the two punters which protect the wing from damage.
They are similar the bit of rubber that the fuel flap closes against.
The rear ones there is “no hope” unless you also have the fixings required, as shown in the photo of one of my spares.
Pictures below may help, instructions are in the the Fitting Accessories manual and use to be on the LR Topx site but that appears not to be available now.