Ford 2011 Mustang Owner's Manual page 160

Seating and Safety Restraints
cushion when the child is seated in it. Keep the tether strap just snug
without lifting the front of the child seat. Keeping the child seat just
touching the vehicle seat gives the best protection in a severe crash.
Perform the following steps to attach a child safety seat to the tether
anchor:
For Coupe only:
1. Route the child safety seat tether strap over the back of the seat.
For vehicles with adjustable head restraints, route the tether strap under
the head restraint and between the head restraint posts, otherwise route
the tether strap over the top of the seatback.
2. Locate the correct anchor for the
selected seating position.
3. Open the tether anchor cover.
160
2011 05+ Mustang (197)
Owners Guide, 2nd Printing
USA (fus)