Accessing High Low in BarsArray

[sandman]

First things first: Happy New Year to whoever reads this today!

My question: How do I access the High and Low of a non-primary BarsArray?

protected override void Initialize()
{
Add(new Plot(Color.Gray, PlotStyle.Square, "Upper0"));
Add(new Plot(Color.Gray, PlotStyle.Square, "Lower0"));

Add(PeriodType.Minute, 15); //
}

protected override void OnBarUpdate()
{
Upper0.Set(Instrument.MasterInstrument.Round2TickS ize(Highs[1])[0]);
Lower0.Set(Instrument.MasterInstrument.Round2TickS ize(Lows[1])[0]);
}
The lines in red don't work no matter whether I use High or Highs.
I also tried
Upper0.Set(Instrument.MasterInstrument.Round2TickS ize(SMA(High,1) [1] [0]);
Lower0.Set(Instrument.MasterInstrument.Round2TickS ize(SMA(Low,1) [1] [0]);

I would appreciate some help.
sandman

[NinjaTrader_AlanP]

Hello sandman,

Thank you for your note.

To plot a secondary series high/lower you would use Highs[1], Lows[1], to refer to the highs/lows of the 2nd series added.

See,

https://ninjatrader.com/support/helpGuides/nt7/?highs.htm

I have attached a screen shot of an indicator I set up as well as attached that indicator.

Please let us know if you need further assistance.