Change the dual rates on channel 5 from high to low. press the "Y" key on your keyboard, or display the radio gadget and watch what happens on the switch bank when you press the "Y" key. Then find the radio switch that does the same.
The DX6 G2 may not have this channel mapped. You only have gear and flap channels. You would have to use one of those when editing the radio setup. It would be easier to just use the "Y" key since you are new.