First unpack the kit, if you have not already done so:
gzip -d < Getopt-Long-x.y.tar.gz | tar xf - cd Getopt-Long-x.y
Getopt::Long can be installed with:
perl Makefile.PL
make all test
make install
This will install Getopt/Long.pm, newgetopt.pl and the Getopt::Long documentation. Note that "make install" will usually require super user privilege unless your Perl is installed in a location you have write access to.
It is also possible to use the CPAN or CPANPLUS tools to install Getopt::Long directly from CPAN, e.g.,
perl -MCPAN -e "install Getopt::Long"
RPM fans can try "rpm -ta Getopt-Long-x.y.tar.gz".
The kit contains an "examples" directory with some program skeleton files that can be used to start writing application programs. It uses Getopt::Long in a standard way, automatically providing version and help information. For the latter, it uses the Pod::Usage module to extracts help texts from the embedded documentation. The Pod::Usage module is part of standard Perl as of Perl version 5.6. For older versions of Perl, it can be fetched from CPAN. Use http://search.cpan.org/search?dist=Pod-Parser.