sorry for delay, have been travelling and my mobile computer is broken …
Thank you very much - that’s what I was missing, would be a good thing to include this in your download page for dummies like me 
I was unsure because of this paragraph in your instructions:
While Rapid Photo Downloader’s installer will automatically download and install most required Python modules not already found on your system, there are some it cannot install. You must install these Python modules and a few other programs prior to installing Rapid Photo Downloader. The Python module requirements are the Python 3 versions of: (…)
and feared I missed something of that.
Now I have a detailed look on the user interface and will start to configure it.