for foam or pepakura? on the top bar of this site, there's a bar that says "The Armory". we store all of the resources there.
on the left side of the armory, there's a list of Halo games, click "Halo Reach", and find your files.
Everything you need is listed ......HERE. If you never did pep before.......you might not find it so easy. I would start w/ a small piece of armor first. Hand plate, shoulder or knee to start and get the hang of it, then move on to larger pieces......