Second row, DS.
Lift up the second row seat, pull up the carpet and you'll see the large round plate that provides access to the pump.
IIRC it is held on by three screws.
AFTER first determining that a fuel pump needs to be replaced, its not a difficult job, but there are some safety concerns.
Here is a quick write up...from when I did mine: Thank You Toyota! ...Fuel Pump Replacement.
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