Lexus LX570 Manual page 154

1-7. Safety information
STEP 4
STEP 5
If the child restraint system has a top tether strap, the top tether
STEP 6
strap should be latched onto the top tether strap anchor. 
(P. 149)
154
LX570_U (OM60F86U)
Fully extend the shoulder strap and
then allow it to retract slightly into
the ALR lock mode.
Lock mode allows the seat belt to
retract only.
While pushing the child restraint
system into the second seat, allow
the shoulder belt to retract until
the child restraint system is
securely in place.
After the shoulder belt has
retracted to a point where there is
no slack in the belt, pull the belt to
check that it cannot be extended.