Before the bulb can be replaced, the plastic cover over the headlamp must be removed; see the section "Bulb replacement".
Never touch the glass part of the bulbs with your fingers. Grease from your fingers is vaporised by the heat, coating the reflector and then causing damage.
Detach the headlamp's round rubber cover.
Unplug the connector from the bulb.
Detach the bulb by pulling straight out.
Replace the bulb.
The guide pin on the bulb must be facing straight up when it is inserted into the socket.
Press in the connector.
Refit the headlamp's round rubber cover.