Let's consider this XML.

<acme>
  <name role="main">Bugs Bunny</name>
</acme>

Data::Dumper can be used to understand how XML::Simple is interpreting the XML. Here is an example of how to use Data::Dumper.

#!/usr/bin/perl
use strict;
use warnings;
use XML::Simple;
use Data::Dumper;

my $xml= XMLin("example.xml");
print Dumper $xml;

Which will produce the following.

• "name" is the root key
• "content" and "id" are child keys below the root key
• "Bugs Bunny" is a value of the "content" key
• "1" is a value of the "id" key 
• Data inside of { } is interepreted as a hash

$VAR1 = {
          'name' => {
                     'content' => 'Bugs Bunny',
                     'role' => 'main'
               }
        };

To loop through each root key:

foreach my $root_key (keys %{$xml}) {
  print "$root_key\n";
}

Which, in this example, will print "name".

name

To loop through each child key.

foreach my $root_key (keys %{$xml}) {
  print "root key = $root_key\n";
  foreach my $child_key (keys %{$xml->{$root_key}}) {
    print "child key = $child_key\n";
  }
}

Which, in this example, will print the following.

root key  = name
child key = content
child key = role

Or, if you already know the child key, you could do this.

foreach my $child_key (keys %{$xml->{'name'}}) {
  print "child key = $child_key\n";
}