i just did this to my 97 yukon
jack the vehical up and secure it on jack stands
remove tires ( front or rear which ever axle your doing first )
the front shocks are held in place by a bottom and a top bolt w/nut
i had to use lots of PB blaster on mine and an electric impact
remove the old shock and replace with the new shock
for the rear it was a little more difficult becuase the lack of space and the
retainers gm used on the bolts
but basically there are 2 bolts in at the top of the shock ( 14mm i believe ) , if you snap the little retainter clip you will have to get your tinniest cousin/child/or kid from your street to get there hand in there cause there is zero clearence for man hands and, clamp on to the back half of the retainer clip with vise grips and try again
this didn't work for me si o got out the dremel and cut the bolts off and replaced them with a new nut and bolt
the bolt on the rear axle is again a PITA lots of PB blaster and impact wrench
put your wheels back on torque them to spec and enjoy your new shocks