Editing Main Navigation

I'd like to change the main navigation of my site, and need a little more guidance than is in the codex as I'm new to php.

Is this the part of the code in the header.php file that I would alter to customize the navigation?

<?php echo display_js(); ?>
</head>
<?php echo body_tag(array('id' => @$bodyid, 'class' => @$bodyclass)); ?>
<?php plugin_body(); ?>

How should this code read if I want to do a few simple changes like "Browse Items" to "Items" as specified in the codex? Although the snippets below make sense to me, I need a little help with what the code should look like in the larger context of the file.

http://omeka.org/codex/Editing_the_Main

many thanks!
Karen

My apologies--I just figured out that it would be much, much easier to use the administrative panel to customize the navigation. It worked beautifully! Karen