The lever for the reclining seatback is located on the outboard side of each seat.
To adjust the seatback, lean slightly forward to lift your weight off the seatback. Pull completely up on the lever until it stops, and lean back to position the seatback to where you want it. Release the lever to lock the seatback into place.
But do not have a seatback reclined if your vehicle is moving.
Caution: Sitting in a reclined position when the vehicle is in motion can be dangerous. Even when buckled up, the safety belts cannot do their job when reclined like this.
The shoulder belt cannot do its job because it will not be against your body. Instead, it will be in front of you. In a crash, you could go into it, receiving neck or other injuries. The lap belt cannot do its job either. In a crash, the belt could go up over your abdomen. The belt forces would be there, not at your pelvic bones. This could cause serious internal injuries. For proper protection when the vehicle is in motion, have the seatback upright. Then sit well back in the seat and wear the safety belt properly.