Remove the left seatback.

To accomplish this, the seatback needs to be free of the mounting bracket toward the inside of the car (see previous step).

The seat needs to lean forward then pushed toward the center of the car to release it from the side of the vehicle.

See the pics to get an idea of the angle needed and what the mounting pin looks like on the side of the vehicle.

A couple important notes about my pictures:

The picture of the seatback leaning forward shows the seat bottom being used as a support - this was for the photo only to give you an idea of the angle. When removing the seatback, the seat bottom needs to be all the way forward.

The picture of the seat (removed from the vehicle) lets you see inside the hole that engages the mounting pin. There's a piece of plastic trim missing from this photo. My trim broke during a prior removal attempt...