Copy this code and paste it in your HTML
register:
<?php
register_nav_menus
( array( 'primary' => __( 'Primary Navigation', 'primarynav' ),
'secondary' => __( 'Secondary Navigation', 'secondarynav' ),
'footer' => __( 'Footer Navigation', 'footernav' ),
) );
?>
display:
<?php wp_nav_menu
(array( 'theme_location' => 'footer'));
?>