One trick I learned here for making a module that you can "run":

package MyPackage;

# if invoked from the command line, call run() with
# command-line input

__PACKAGE__->run( @ARGV ) unless caller();
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I have tried creating a .pl file and the keyword "package" throws errors. I have tried creating a .pm file, then putting main code (even "print 'Hello World', before the "1;", and this throws different errors.

You'll have to be more specific; I do those things all the time without a hitch.