I’d start by wiggling the outside casing to try and see where it’s attached to the frame of the machine and take out any screws holding it down, using a little dish or some folded up tin foil to hold all the screws of one type, then slap on a lil masking tape on that bowl, label it A, then another bit of tape on the part it came off, or near the holes they came from, and label those A, and then B for the next part, etc., all the while trying to free the casing that holds the on off switch.

Don’t disassemble more than ya have to. Another poster said they found teardown videos for devices of this make, I’d watch through those a few times to see if any of em get to the switch you’re trying to fix beforehand, so you got a better idea of what to expect and maybe you can minimize the amount of work you have to do to get it at it.

Take it slow and steady, there’s no rush. Anything that can be assembled can be disassembled.