Shamik--The grinder is for dry beans/seeds only. Keep the unit and the cord away from water, and don't put water inside it--it could leak down into the main mechanism and cause a serious electrical hazard. Be careful!
You fill the well with beans, put the clear plastic dome in place, and apply pressure to the toggle on the side that acts as an "on" switch. As long as you press your finger there, the grinder grinds. (10 seconds for drip grind, 20 seconds for automatic coffeemaker grind.) To stop, remove the pressure. The retractable electric cord goes inside the body of the unit for easy storage.