How do change light bulbs on vw touran?

Without year of vehicle and which bulb(s) you mean, this question is way too vague. That said, purchase the correct replacement light bulb(s) first, before disassembling the vehicle. See sources and related links below for replacement light bulb information. Then consult your owner's manual for the replacement procedure. As simple as it sounds, the owner's manual is the best place to start for light bulb replacement instructions and illustrations.