How tu use : in the input tab choose youe prefered lenght and the volume' index ticker you want to display. TVOLQ for the NASDAQ Composite total or TVOL for the NYSE Composite total .
On chart, choose to display the indicator in a new pane.
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.