Its a thumbwheel on the steering wheel. Left one I think. Turn it and each stat rotates in turn. Pressing the wheel resets the data to zero
I have 2.0 Litre Diesel (I84) Quattro with S Tronic, depending on the setting of the car (its has 5 different set up modes) in auto I achieve 54 mpg as an average with 56, a personal best. In sport mode forget MPG, just enjoy the ride. 'Breath taking' for a diesel!