Pull the seatbelt nice and tight, then route the shoulder belt around the back of the car seat and through the blue seatbelt guide at the back of the Toddler Car Seat Group 0+1+2+3, making sure there are no twists in the seatbelt. Pull out any slack in the seatbelt to get it in securely. You can watch our video HERE on how to install a car seat using the seatbelt.https://www.welldon-baby.com/t....oddler-car-seat/todd