This script just changes the background of the chart to show Trending(Green) / Range Bound(Red) Regions.
The concept is very simple, al each candle we look at the size of the candle and use a moving average of these candle body size (ABS (close-open)) and compare it agains a double smoothened average, i.e. moving average of this average to find trending or not trending periods.
I find it useful primarily for entry in options, a green background is more favourable for option buying and a red background is more favourable for option selling.
This script tells you nothing about the direction of trade.