You've got to pull up the carpet. Now I forget exactly how I did it but I knew I needed to pull it up when I started.

I took out the seats, star torx bit, I forget what size. Un plug the seat.

There are 2 plastic plugs that pop out. I used a pry bar underneath the plastic as not to scratch it to pop those out.

then just peal the carpet away from the moldlings and trim and you should see the sub container in the back wall.

sorry no pics