The red and green LEDs show the status of the digital output line.
Red: low (0v)
Green: high (5v)
The slide switch and push button will set the digital input state.
Slide switch position
Left: low (0v)
Right: high (5v)
Push Button position
Down: low (0v)
Up: high (5v)
Note: For the push button to function properly, the slide switch need to be set to the left (high).