Upload the firmware and your diagram to controller.
Turn the main controller power by setting 3-pos switch on demo board in position Power (see label 12 on picture below)
Select the push button polarity by setting 3-pos switch on demo board in properly position (see label 13 on picture belo)
Then if you press any push button, voltage with selected polarity will applied to appropriate controller's channel.
With attached diagram:
Set push button polarity to +12V then press and hold CH0 button for 200 ms or longer and release for 200 ms or longer for switch CH1 output on and off. The controller on-board LED will indicate debounced CH0 state.