Installing sun tubes is stupid easy if you have done any sort of remodel work before- built a deck, gutted a bathroom? You need a good(note the qualifier) jigsaw or, if you are a surgeon with a sawzall, that works too. Obviously, you are going to need a drill, hammer, drywall saw etc...The only real thing to watch is not to break the shingles surrounding the hole as you still have to slide the flashing up under them to maintain the lapping. I would actually advocate cutting from the outside for that reason- when you cut shingles for the inside they have a tenancy to crack as your lads can get hung up underneath them and shake them instead of cutting them. You don't need a circle jig- the tube comes with a template and there is some wiggle room on the cut. Again, good jigsaw, right blade- full power, blast through the shingles and sheathing in one cut. Keep the shoe of he saw pressed down on the shingles to keep them from shaking loose. You'll need a flat bar to pry up the upper shingles- then tjs just some screws and sealant. Easy.