ok well some pegs have threads on them so you can just screw them right onto the axle. but for the most part you are gonna take off your bolts on that wheel, slide the pegs on the axle, then put the bolts back on. use a socket wrench with either a 17mm or 3/4'' head and use an extender on the socket so that you can reach the axle through the peg.
and for future reference, try not to call them stunt pegs, they're just pegs.
also on the back wheel make sure to pull the wheel back so the chain isn't loose.