How to substitute old wordpress menu by wp 3 menu the right way?

Question

I have a wp theme with this menu in header:

    <div id="header_nav">
        <ul id="nav" class="clearfloat">
            <li><a href="<?php echo get_option('home'); ?>/" class="on">Home</a></li> 
            <?php wp_list_pages('title_li='); ?>
        </ul>                       
    </div>

I followed the tut here http://www.wpbeginner.com/wp-themes/how-to-add-custom-navigation-menus-in-wordpress-3-0-themes/

and replace it with

<?php wp_nav_menu( array( 'sort_column' => 'menu_order', 'container_class' => 'menu-header' ) ); ?>

but it doesn't style at all like previously. So is it really the right way ?

Answer 1

<?php wp_nav_menu( array('theme_location'  => 'primary or whatever you set it', 'sort_column' => 'menu_order', 'menu_id' => 'nav', 'menu_class' => 'clearfloat', 'container_id' => 'header_nav' ) ); ?>

Codex if your friend! http://codex.wordpress.org/Function_Reference/wp_nav_menu