Mine---not like yours---has two screws holding it in on top. I accessed them by removing the flooring in the above cabinets. Then it just swings down and lifts out of a bracket in back.
I tried looking for manuals for your unit on-line but every website wants me to add a program to download. You might look on-line and see if you are interested.
Hopefully someone will come along soon who has your exact uint. Good luck.
I do all my own stunts
03 Dolphin LX 6355, Workhorse W22, 8.1 vortec, 04 CR-V, Blue Ox, Brake Pro----Norm, Barb and
Doc(He's a PhD)