No, you don't have to remove the front seats nor do you have to put the top down.
Feel along the front edge of the back seat bottom. You will feel two wide, flat buttons. Push them in at the same time and lift up on the seat. It will come right out.
The seat back is held in with two bolts, one in each lower corner. You might need to push up on the bottom of the cushion to see them. Take the bolts out and the seat back slides up and out.