> ...I get
> the message - python3 is not recognized as an internal or external command,
> operable program or batch file.
>
> Any ideas with what I'm doing wrong

Do you have any more luck with typing "python3.0" When you installed Python, was there an option you could select that said something about installing the command line tools, that was a bit too subtle to notice the first time Those are the main previous issues I'm aware of.