depends on which yr was your landy. on Td5s all the holes you ever need to mount the folding steps are found on the chassis and body.
now, if you look carefully under the landy, you'll see just behind the bottom about 30cm from the door post there's a mounting hole. it's abt 5cm from the edge on a rail attatched. the step goes there.
now, you see you have a hex nut which fits into the hex hole in the chassis. it sits very loose in the hole. but not a problem, that anchors the support bar from the step to the chassis and is very very difficult to get it in.
so mount the step first, then loosely bolt the support bar to the step, yes the middle hole, and the grab the step with both you hand, assuming you already bolted the step onto that rail i was talking about. and now, push both your legs stepping on the chassis.
effectively, you are off the floor with butt in the air and then, either use one of your foot to position the bar correctly or get someone to help you with that. quickly tighten the screw into the hex nut on the chassis.
phew now that was tuff. sweating like crazy.