In the video, a person is seen demonstrating how to install a car seat in the back seat of a vehicle. The person starts by placing the car seat on the floor of the back seat and then proceeds to secure it in place. The person uses a strap to fasten the car seat to the back of the seat, ensuring that it is secure and will not move while the vehicle is in motion. The person then adjusts the car seat to ensure that it is at the correct height and angle for the child who will be using it. Throughout the video, the person is careful and precise in their movements, ensuring that the car seat is installed correctly and safely.