take off the 2 bolts holding the brake caliper on lift it up off the break drum remove the old brake pads . Use a c clamp to push the plunger back in incert the new pads bolt it back in place.
I have done this and it was pretty easy. It takes about three hours. The best thing to do is buy a manual or go to the auto parts store and read it. You probably will have to buy a large Allen wrench...
Unfortunately you will need to go buy the torx head socket to do it. Probably the same as mine (2002). if so it is the T55 size. Phone your local Chevy dealer and make sure the size.