noob warning: Garmin Edge, Monkey C, Visual Studio cookbook

Is there a cookbook anywhere on how to create a data filed for a Garmin Edge product in Visual Studio?

I've succeeded in running the "Your First Connect IQ App"

https://developer.garmin.com/connect-iq/connect-iq-basics/your-first-app/

but that does not introduce any concepts whereby I can create anything analogous. Exacerbating my ignorance is everything being so watch focused.

I've found hints on the subject, but all those are using Eclipse, not Monkey C and I have no familiarity with that product either.

As example of what I might like to do it display an improved ETA. Here's an attempt at pyhton-esque pseudo-code.

trueETA = time_of_day + <Time[-1]> - <Time{next<Trackpoint>}