Caution: you're likely to do some minor damage to your coffee machine. Consider twice if you really need to get into this compartment. It only contains the cables, valve, and the pump.

For getting into the centre compartment, you'll have to have both the top and bottom already removed.

Next, remove the three screws in the bottom compartment. This should allow you to remove the second bottom plate.

Optional: To make your live easier, I'd recommend to fully remove the bottom plate. Remove all plugs from the toggle switch and the PCB. I would recommend to label them (e.g. with the labels on the PCB).

If you messed up/forgot to label, you can check out the wiring diagram in the last step, but beware that the cables might have different colours for you!