GMC 2015 Sierra Denali Owner's Manual page 105

3-52 Seats and Restraints
7. If your child restraint has a top
tether, follow the child restraint
manufacturer's instructions
regarding the use of the top
tether. See Lower Anchors and
Tethers for Children (LATCH
System) on page 3-38 for more
information on using the top
tether anchors.
8. Before placing a child in the
child restraint, make sure it is
securely held in place. To check,
grasp the child restraint at the
safety belt path and attempt to
move it side to side and back
and forth. When the child
restraint is properly installed,
there should be no more than
2.5 cm (1 in) of movement.
To remove the child restraint,
unbuckle the vehicle safety belt and
let it return to the stowed position.