I bought a used Peavey Classic 30 a bit ago. I bought a tube guard, and the directions suggest removing the tubes before installing it. I am a tube newbie, and was wondering if putting the tubes back in will be difficult or you have any advice?

Changing tubes is very simple. Just remember which ones came from which sockets, and gently pull them out after the amp has been off for a while. To reinstall, align the pins on the tube with the holes in the sockets (they can sometimes get a little bit bent), and slowly push them back in. Easier than changing a lightbulb.
It shouldn't be THAT hard, but I'm sure you'll get through.
Hey, was it the old Peavey C30? with the metal peavey logo infront of the amp?