GMC 1995 Suburban Owner's Manual page 244

Good Battery (-)
Heavy Metal Enaine Part
0
Attach the cable at least 18 inches (45 cm) away from the dead battery,
but not near engine parts that move. The electrical connection is just as
good there, but the chance of sparks getting back to the battery is much
less.
Now start the vehicle with the good battery and run the engine for
Try to start the vehicle with the dead battery.
awhile.
If
it
won't start after a few tries, it probably needs service.
Remove Cables in this Order:
2
3
1. Heavy Metal
2. Good Battery
(-)
3. Good Battery
(+)
4. Dead Battery
(+)
Engine
P a r t
Remove the cables in reverse order to prevent electrical shorting.
Take care that they don't touch each other or any other metal.
5-6