Get an expert in to do it!
Is it like some Renaults?
 
Remove the wheel in the arch where the lightbulb is 
Open the bonnet and unscrew the black plastic cover from above the light mount 
Remove the little cap in the wheel arch to gain access to the light 
Unscrew the protection cap from the back of the mounting 
Before removing any lightbulbs, wiggle the back of the one you think is the problem and confirm by looking at the front as to which is moving 
CAREFULLY remove the metal clip from around the bulb by squeezing it either side of the bulb 
Carefully remove the wiring from the back of the bulb 
Take out the old bulb and insert a new one. It doesnt screw, it just sits - safely! Ensure it is square inside the bracket though 
Replace the clip around the bulb 
Add the wiring to the back of the bulb and test.