Push the roller then turn the Tx on. Make sure you are on the model which you are wanting to edit, and go into Switch Select. In there, you will assign the channel to the switch that you wish to use. Most often, and the easiest way to do this is to use Aux2 or Aux3. If you want to use Gear, then you are going to have to make sure Gear is not selected in the gyro menu on the Tx as well as not selected in teh governor menu.
One thing to remember, there will always be power on the red and black wires. The signal wire is what changes when you assign a switch. If you are needing to change the power status on and off, then there will have to be other things involved, and I'm not sure what would be required.