Mode 2 has the elevators & ailerons on the right hand stick with the throttyle & rudder on the left.
Mode 1 has the Elevators and rudder on the left with aileron and throttle on the right.
The G2 controller is sold in mode 1 or 2 format.
In Australia, 95% use Mode 1. Try to learn on whatever is the locally accepted mode, as instructors that can fly mode 1 & 2 are unusual and it needs modyfing their transmitter and buddy box.