Sorry Bill, but this is part of the proprietary elements of the methodology, so I won't give much details.
The starting point is to define the first clusters as a normal range that could be made on the next day. The second clusters are the ranges that could be made on a strong trend day. The cluster strength will give you the expected ease of movement in each direction.
The proprietary details are mostly in what optimal ATR and multiple of ATR to choose and it is different with each instrument. But I hope you get the concept and idea.
Billy