Chevrolet 2009 Silverado Owner's Manual page 516

6. Stand the wheel blocks on their shortest ends, with
the backs facing each other.
5-106
7. Place the bottom edge
of the jack (A) on the
wheel blocks (B),
separating them so that
the jack is balanced
securely.
8. Attach the jack handle, extension, and wheel wrench
to the jack and place it (with the wheel blocks) under
the vehicle toward the front of the rear bumper.