Not that much!
We provide you water and soft drinks (or hot tea for winter trips). Each buggy is equipped with a first aid kit the leading buggy has the required tools needed in case a buggy gets stuck. Your leader has experience of off-road terrain and is trained to handle any situation that may occur.
There are however some items you should bring:
A camera, the strongest available sun block, a scarf to put around your mouth and nose (especially for mountain trips) a long sleeved t-shirt (to protect you from the sun). You do not need to wear long trousers, shorts will work perfectly well, or closed shoes, sandals will be adequate.
In winter, don't forget to take a jacket, as the weather can be cold or wet.