gomi made it pretty easy to use his framework to create your own custom indicators. I have written a couple indicators that use Gomi's framework. Search for XavNPDDO or XavDeltaOscillator. These are very simple examples on creating a GomDeltaIndicator.
Don't forget to use
public class YourIndicatorName : GomDeltaIndicator or public class YourIndicatorName : GomRecorderIndicator
It took me an hour to figure this out lol