I looked again last night. It looks like the rear cushions are easy but the rear seat back may be a little harder. It appears that you unbolt the seat back then remove the cargo area trim (Somehow) from the back of the seat from there it should be pretty straight forward.
I've done it before on my previous vehicle - its not hard, but kind of like stuffing a greased pig into a sack. If you do it right then its easy. Turn the new cover inside out then start from the top and work your way down, making sure that you pull out all wrinkles.