Above 0 indicates momentum, below 0 indicates momentum.
Notice the behavior of the market when the range is increasing and decreasing - both on the long and short term oscillations.
The indicator should be used in a discretionary manner along with your usual preferred tools.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.