Easy, you will have a timer set for 15min 4 times a day. I bought a digital timer for this. Now for the water level, the pump will go to tubing, the tubing ataches to the bottom of the tray. Now the tray has a inlet and a outlet, the outlet has adjustable hight capitbilities. So the pump kicks on, fills the tray to the level that the adjustable outlet, and the pump continues to run until the timer kicks off. When the pump kicks off the water runs back down the pump, draining all the water...I hope I described that right...I am medicated at the moment..