How do i unscrew this screw to take apart the bed frame

Depending on your stair, lighting might be the responsibility of the council. If there's a sticker/notice that has a number for "concerns/ complaints", they'd be the right ones to call. If there's nothing posted, it might be a communal thing. Part of the reason I bring this up is that the replacement bulbs for that lamp seemed really expensive when bought in small quantities. (Or maybe that was just me being a cheapskate. From memory, it was just shy of a tenner.)

But a pair of small-ish needlenose pliers should allow you to unscrew them. If you're naughty, replace with a normal bolt.

If your ceiling is high, be careful on that ladder.

Those are levelling legs.

Dishwashers are either held in via screws on top of the dishwasher that attach to countertop above, or that screw the side (look roughly 1/3rd down just inside the DW door) of the dishwasher to the surrounding cabinet.