You have to get your moon buggy from the start point to the finish point by cleverly steering your way around the obstacles, you only have a certain amount of oxygen so you will have to stop at oxygen stations to get a refill of oxygen,  to move the buggy you use 4 and 6 to steer left and right and 2 and 8 to move forwards and backwards or you can use the d-pad. To refill with oxygen you just have to hover over the oxygen station.