Take off the lens.
Take off the turn indicator lens.
Unscrew the bulb.

Remove screw (1).
Loosen screw (2) but do not remove completely.

Push the bulb holder to the rear and pull away from the
side panel.
Remove the bulb holder completely.

Pull off the cable plug.
Bend up the metal tag with pliers and disconnect the
earth (ground) wire.

When installing: Insert the bulb holder, screw in screw (2),
align retaining plate with a scriber or similar tool and insert
the remaining screw.