Lay the stepping stone into, or next to, the installation site and use a pencil to draw a line on it where you intend to cut it.
Put on safety glasses and work gloves, and insert a hand guard over the handle of a brick set. Set the blade of the brick set on the pencil line on the stepping stone. Tap the brick set handle with a drilling hammer three or four times with firm pressure.
Slide the brick set over to another area of the pencil line, and repeat the process until you reach the end of the stepping stone.
Place the blade of the brick set into the center of the score line you created and tap it with a bit more pressure, and the stepping stone will split into two pieces.