The center button is used for paring the device. The up and down arrows are used to increase and decrease cadence respectively. We do however recommend installing the app and updating the firmware first. While not a requirement, there has been a firmware update since the bikes were produced. In our experience, the Automatiq system works so well that once you make any desired tweaks with the app or set your cadence with the CO controller, you likely will not actually use the handlebar mounted controller. Note that you can only connect either the app or the controller--they can not be operated at the same time.