Watch and listen carefully, you can see and heard 3 different types of stone placing. A gentle touch almost no sound, like slide in, normally slide in from one side of a group of stones; A force placement strait down that makes hard contact, usually in a wide open spot of few or no stone nearby; A nice click using fingers, coming in from an angle, withdraw the index finger to making the curve side click, normally right next to an existing stone, it’s also a technique that doesn’t disturb the stone by aiming slightly off using the edge of a stone in order to contact the bottom of a stone at the exact spot. This can also be hard or soft, doesn’t have to force the click.