The clay piece is wet around the edges with a sponge then the metal wheel surface is made wet very slightly then you turn piece upside down , and gently place the piece in the middle and both hands are placed on the outside. The next stage is centering the piece by getting the wheel going and trying to get the piece so its not wobbling about in your hands. I then press on top very gently to create a suction. The clay on the outside is called keys when placed around outside of the piece. This is to help support the piece whilst working on it.