It's pretty straightforward. If it's on the left hand side, there's a cover with one or two screws in the top to remove first. Then open the metal wire retaining clip across the back of the headlight unit (it will stay connected to the unit). The big plastic cover should then just pull away showing the bulbs underneath. Pull the wiring plug off the back of the bulb to be changed. There's another metal retaining clip on the bulb and you need to squeeze one end of it to release it. If I recall correctly, it's quite fiddley to get it open. Once it's off, just pull out the old bulb and put in the new one, making sure that the locating tabs are in the right place. It's very important that you don't touch the glass of the new bulb with your fingers 'cos the grease will cause the bulb to fail early. Just assemble the unit back the same way it came apart.