Linux:: Perl and XML

I am learning Perl and its ability with XML,. Because the structure of my domcument is not too hard, I use:

use XML::Simple;

What I want is to generate an xml output. But it means I need to undestand how to create a Perl structure which can be translate in the XML I want... To do that, I make "reverse engineering" by using this simple script:

#!/usr/bin/perl
   use XML::Simple;
   use Data::Dumper;
   
   my $xs = new XML::Simple(keeproot => 1,searchpath => ".",
      forcearray => 1, keyattr => [key, tag]);
   my $ref = $xs->XMLin("point.xml");
   my $xml = $xs->XMLout($ref);
   print "\nHash dump with 'keyattr => [key, tag]':\n";
   print Dumper($ref);
   
   print "\nXML output with 'keyattr => [key, tag]':\n";
   print $xml;
   exit;