GMC SIERRA DENALI 2002 Manual page 97

Shifting Into PARK (P)
CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake firmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle won't move,
even when you're on fairly level ground, use the
steps that follow. If you're pulling a trailer, see
"Towing a Trailer" in the Index.
2-24
1. Hold the brake pedal down with your right foot and
set the parking brake.
2. Move the shift lever into PARK (P) like this:
D
Pull the shift lever toward you.