Place the SensAlert on the base of the car seat with the Doona label facing upwards and insert the seat belt inside the opening, as shown in the photo below. It is important to install the SensAlert correctly, so that its sensors are facing upwards. Installing the SensAlert in the wrong direction will compromise its function. Once installed, the SensAlert will automatically activate as soon as the child is placed on the car seat. If you are using the Infant Insert in the Doona Car Seat & Stroller, place SensAlert on top of the Infant Insert.