The working principle can easily be understood.
There is a "water compartment" at each section. This consists (obviously) of water, but also of a ultrasonic mist-maker hardware and a water-level-sensor. The "electronics compartment" measures the humidity and temperature and decides therefore whether the plants should be "watered" with mist or not.
Status LEDs on the side of the electronics compartment show in which state the system currently is.