1. First, take out the seat belt buckle from the seat gap.
2. Secondly, put the seat back flat. There is a button-shaped thing on the back of the car seat. You can dig the backrest off.
3. Finally, at the bottom of the seat, there is a brace on the left and right, which is pulled up gently. Finally, lift the seat, fold it backwards, and insert the bolt to fix the seat.