Hi David I am confused about what you are doing at this point. I am not sure what you are referring to when you say you don't see any response on the screen from the "original sketch." Do you mean the simple serial echo I posted above? If so, exactly what do you see on the serial monitor screen?
The sketch you attached to your last post appears to be part of the serial echo sketch pasted into the TMCC snippets sketch. It's hard for me to know what's going on if you're mixing them together like that....
It also appears your Arduino software is fairly old (looks like 1.8.3). It can't hurt to update to the latest release (1.8.15).
