rear seat mounts

Could someone please advise me on the rear seat mounts for my disco td5, I have bought s/h rear seat set have all the bits to fit them, their is some pointed steel things that fit in somewhere, ie what way do they point where do they fit in inside the mount or outside, I have checked rave but not enough detail to see many thanks in advance.By the way Im converting a td5 commercial to a 5/7 seater so dont have the old seats for reference.