With the simplified creation tool, you can only use built-in indicators (which no contained any candlestick patterns ones) or customized ones (from the library of this website for instance). But in order to get the signals when a pattern occured, the indicator need to return a value to be used by the trading strategy to launch a new order.

Can I ask which indicator or candlestick patterns codes you’d like to use?

You can find many of them there:

https://www.prorealcode.com/prorealtime-indicators/candlestick-patterns-recognition/

https://www.prorealcode.com/prorealtime-indicators/candlesticks-patterns-indicator/

the links Nicholas provided contain the code for the patterns you are interested in.  It can be daunting to have to code when you are new to it, but here it is just a matter of putting together a simple jigsaw from pieces that someone else has already created.  If you take an existing simple strategy from the library and replace the logic (the part where it tests the indicators) with the code for the candlestick patterns you should be able to get it working and ready for back testing.  If you get stuck me or someone else can help you out.

This is the code to detect a Marubozu candlestick:

marubozu = abs(open-close)/range>=0.95