I installed this same mount and had a hard time as it came with no instructions, and I had no experience. I found some instructions on the internet for another similar mount and it helped. Do a search for something like "install M14 scope mount" or something like that. I found tolerances on the mount to be very tight in terms of mounting it on my M14. The retaining pin you refer to does require a punch. And be sure to punch it outwards from the inside of the reciever out, not into the inside of the reciever! On my rifle at least, getting the mount to slide into the stripper clip guide retainer was very tough, requiring me to use WD40 repeatedly and lay my rifle down on it's side on a 2x4 and hammer it vigorously with a heavy hard rubber mallet. I was actually concerned it would split the reciever it was so tight. Once in, I put in the new little retaining pin it comes with and tightened the two allen head screws. I felt at this point the two screws were a bit redundant as the whole thing was soooo tight. I think I could have set it up on a .375 H&H and it would not have moved. Then I set up the rest of the sight, which went easily. Once I was sure everything was centered and it looked good from all angles, I marked where everything was, took the mount back off the rifle (obviously not the crazy tight stripper guide part) and cleaned off all the lubricant the mount came with. Then I reassembled with a generous amount of red loctite on all applicable parts. I reassembled as tight as I possibly could (including an extra 1/10th turn with huge vise grips on the knobs) and re-inspected and then let the whole thing sit for 48 hours. It all seemed rock solid, and after my first day at the range it still seems like I could jump on it and it would not shift. Good luck.
