Trading View Pine Editor

[ProjectRED]

Hello,

 

I doubt anyone here has used this pine script editor for back testing day trades. https://www.tradingview.com/study-script-reference/

 

But im trying to write a script that prints a vertical line every 15 candles on any time frame. 

 

Thanks if you can help me

[PeterBocan]

Well, the first question is: What sets the very first candle? Is it from the whole hour, or Current time + 15 candles?