Candles are green when is increasing and red when it is decreasing. All lengths can be adjusted in the input menu and there is an option to plot the signal line.
The rules for using it are pretty simple:
1.Buy on Green
2.Sell on red
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.