Place the tumbler on the rotary attachment using the chuck. I place my tumbler leveler along the top and use the riser on the bottom to ensure the tumbler is level. I manually measured the top, middle, and bottom, took an average of the three numbers, and then placed the value of that in the distance box, measured around the tumbler at the largest perimeter using the tape, then put that amount in the perimeter box, make sure the design fits the cup, with it being black i had to invert this image.