You can use a siding nailer, shoots a full-head nail, wire-collated. The gun may be possible to rent, and you can get stainless nails for some of them, which is what you'd want.
I hate to say it, but you could probably also use a narrow-crown stapler. Nails would be lots better, IMO.
Casey

Thanks for the advice. Why do you prefer the nails over staples? Do staples pull out over time as the cedar expands and contracts?

I don't see many galvanized staples out there, I guess the stapler option would require stainless steel staples?

I use stainless staples or stainless ring shank nails.

If you want unstained shingles, consider stainless or aluminum nails, or stainless staples.

I used to be anti-staple but I'm open to either now.

You can rent a gun, but depending on how much siding you have to do, buying might be a better option. You can always resell it on eBay when you are done.