The first time out with these will make you swear. You can do a modification to the bolt studs if you want to press them out of the front diff flanges:

http://personal.utulsa.edu/~nathan-buchanan/93fsm/suspensionandaxle/20removalo.pdf

For this one, you'll want a pry bar to get the CV axle to clear the bolts to drop the axle out. The cheap mod is to press out the diff bolts, grind the splines off, then reassemble with lock/nut for easy removal next time. You still want them to fit snugly thru the flange, but now they're removeable.

The inspection per the book is to put the axle in a vice, and try to twist it for play. What you're also looking for here is to dig the grease out to check for road debris, and see if the bearings (look like big marbles on the outboard side) are jacked up.

To break these down to put on boots is a BEAR. After attempting that once for a non-split boot kit, I've said screw it, and just took the axles in for a core return, which is about $110 or so.

Ask if that NAPA kit is a split boot you can wrap around and seal, or if it's the slide-on (whole) type.

Remember to give your hub body a quick cleaning and light greasing before putting back on; antiseize for the cone washers.