Optional this first bit, but undo the 2 screws on the front panel which hold the air duct to it. (sorry this is starting on the driver's side)
Pull it out and take the trunking to the airbox off, which just pull s up, quite stiff but don't be afraid. The bonnet release cable is here somewhere and clips in to the plastic part, take note of where it runs either under or over it as you may make it tight and not be able to open the bonnet next time very easily.
Now you can un-clip the silver clip which holds the flap concealing the wiring and bulb. Unplug the wires and then around the bulb is another clip which is held to the lamp so don't pull it our, but pinch the 2 curled ends towards the middle of the bulb and it should release.
Take not of how the 3 pins (i think it's 3) of the bulb are located i.e. 1 at the top and 2 at either bottom side.
Reverse for fitting.
It was about 9 months ago I did it but I think it's fairly easy. If you can be more specific as to waht you have got stuck with I may be able to help.