The Three button project is pretty easy to understand. But when functions are covered, that actual data flow is really obfuscated in the way "Chapter 3" is written! What is the data flow here? Where can I see an actual, graphical diagram as to where values are being passed and returned? I see nothing! Can someone draw me an annotated diagram withing a code box? Thanks.

All I see, is more and more piciune detail, which, although breaking down the actual process does NOT explain returning and calling function data and how the data gets actually distributed within all the variables declared, and all the value assigns and changes. I'm just simply not understanding it.

Building a Method: TryitOut is super confusing because no actual DATA FLOW and subsequent results are explained.
Can someone draw me an actual diagram with arrows, as well as values on the arrows within the Circle Area program?

Thank you. I'm badly, SEVERELY stuck here and losing my mind! It's just simply not truly explained.

Regards,
bodycode