The seat bottom is removed by FIRMLY pulling upward at the two retainer brackets on either side of the front edge of the seat. If you slide your hand under the lower front edge you will feel where they are at.
To remove the seat backs you have to first remove the outboard bolsters by pulling them outward (toward the front of the car) at the top and then upward. Once they are removed you will have access to the folding seat back retainers. Pry the outboard grommet toward the inside of the car, pull the seat upward at the outboard grommet, and then pull it outward from the center pivot. Both sides are configured the same way, the only difference is that you have to remove the bolt for the seatbelt on the driver side seat back.
There is a metal frame under the seat bottom. You could remove that also but it protects the charging equipment and other more sensitive devices that are under the back seat.