It was a bolt of lightning when I realized that Script::Singleton was another script, and all I needed to do was copy that script from the CPAN.org site**, save it in a local directory, and then have my script run his script.

As you've alluded to later on in your post this is in fact a module rather than a script - it is to be used rather than run. As such you should really install the module properly rather than just copy a single file. This (installing the module) will save you from your current problems of hunt-the-file.

Here in the Monastery there are several Tutorials for installing modules and while they are quite old now, the principles are sound. See also the Perl FAQ: How do I install a module from CPAN?

In the case of Script::Singleton you will also need the dependencies, if those are not already installed. Following the installation process as in the documents referenced above will at least inform you of what you are missing and in some cases, automatically install those dependencies as well.

Hopefully this helps to clarify things but do come back if you have further questions or get stuck.