Been a while, so I am not totally sure, but give this a whirl. While straddling the driveshaft tunnel facing the trunk, first push the rear seat bottom straight back, then lift up, then pull forward. Rotate the cushion front edge up as you pull it towards you. The lower cushion should come out the rest of the way. This will also expose the lower part of the upper cushion. There may be a bolt or two holding it down, otherwise, it slides up and out. Better to remove the armrests, if you haven't already.
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