Radios traditionally were bought pre-configured for mode 1 or mode 2, with mode 2 being typical for USA flyers with the throttle and rudder on the left stick and aileron and elevator on the right stick. Other regions of the world use different conventions, hence the different mode choices. With OpenTX for the Taranis, four stick modes can be conveniently selected by the user in the configuration of the radio. THIS IS A CRITICAL CHOICE in the setup of the radio. It determines which control axis of the air craft is controlled by which gimbal. Make sure that you select the mode with which you are accustomed to flying.