Ne, ne, ne. Dan, no nailgun on cedar shingles. There are nails for just such a purpose. The tops of the shingles are very thin and you need a headed nail to hold them properly. There are guns that will accomodate, but they're too expensive for a little job ($250-300).
I, too, thought the actual application of the shingles was pretty simple. I was wrong. While still not rocket science, I'd check out a HOW-TO book chapter on it.
Russian shitheads! Now I can't carry my Dutch oven around in my backpack anymore!