2013 Toyota Tundra CrewMax Owners Manual - Page 124
2013 Toyota Tundra CrewMax Manual
Page 124 highlights
1-7. Safety information Center rear seat Latch the hook onto the inner anchor strap ring and tighten the top tether strap. Make sure the top tether strap is securely latched. Before driving 1 Inner anchor strap ring Lower the head restraints of right and center seats.