This script is only suitable for 24x7 markets, it is not suitable for markets with closing times and weekends, or gap markets where trading is not active. In fact, the calculation of calendar times is used, not suitable for markets with closing times.
Use the settings to indicate what the start time of bar 1. The indicator will produce many vertical bars, even in addition to the end time of the graph.
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.