What?

I did not quite understand what you mean. I did mention I'm totally new to this. Could you care to be more explicit pls.

Thank you very much

No. Read perlintro, use, Tutorials: Simple Module Tutorial... Where and how to start learning Perl

Perl (and really all code languages) are made up of various 'sets' of functions. You can bring in one of these sets with the 'use Text::ParseWords;' line, which enables you to use one of the functions in that set: 'quotewords'. I.e. if you remove that 'use' line from your file, the quotewords line will give you an error.

Code modularization and reuse are definitely important aspects of coding. I would say you should start to look into these topics in earnest once you have gotten comfortable writing a few 'basic hello world' examples from scratch on your own. In short: most advanced functionality you are looking for will be package in some module somewhere nowadays :). Hope that helps!