How do I properly install the Graco Extend2fit rear-facing?

To install the car seat in rear-facing mode, make sure LATCH straps or vehicle seat belt are routed through the rear-facing belt path marked with a blue label. Ensure the base sits flat on the vehicle seat and secure it tightly; if you route the vehicle seat belt, test for tightness by moving the car seat side-to-side and front-to-back to ensure movement is no more than 1 inch (2.5 cm) at the belt path.