Toyota 2013 Prius Owner's Manual page 243

1-9. Safety information
Removing a child restraint installed with a seat belt
Child restraint systems with a top tether strap
Secure the child restraint system using a seat belt or the
STEP 1
LATCH anchors, and do the following.
Foldable type outside seats
216
PRIUS PHV_OM_OM47787U_(U)
Press the buckle release button
and fully retract the seat belt.
Adjust the head restraint to the
upmost position.