Well, take a look under the bonnet and you will see the rear of your headlights/lamp. There is a black cover that you will need to unclip. There are two clips running vertically to the cover. Pull the one on the left and the other on the right and take the cover off. Once there you will see the bulbs. Here is the odd part of your installation. You need to unclip the correct bulb (make sure it is the sidelight), take it off its socket, replace and reverse the instructions for putting things back on.
Then go for a spin to the Mumbles with your lovely
Ibiza and pull lots of Swansea girls!