…we use a Phillips screwdriver to unscrew the screw,...
…we take out the switch and disconnect the wire from it.
We install the new switch in the reverse order.
To replace the interior light, remove it (see Replacing the interior light bulb). Remember the order of connecting the wires to the lampshade.
[The text is copied from the online resource: vazbook]
We disconnect the wires from the faulty lampshade and connect them to the new one.