If you're anything like me, pictures will be the most help.
Try this website:
http://www.handcraftedgreetings.com/irisinst.php
Something to remember is that you want that folded edge to be nice and sharp. I did this with a class of wild childs and they all found it manageable enough to engage them and went kind of crazy making all kinds of patterns. It almost became its own epidemic! Once you catch on, you're addicted.