Follow these steps
1) Put this code in your function.phpf
register_nav_menus( array(
'primary' => __( 'Primary Navigation', 'your_theme_name' ),
'secondary' => __('Secondary Navigation', 'your_theme_name')
) );
These must be a function which will be registering menus. look for that and just add another code line like its in above code.
2) Updating function.php will create an option for secondary menu in Appereance–>Menu option.
3) Create another menu like how you want. and make it as Secondary menu from option at left. Save it
4) Open page where you want to display secondary menu and paste this code
5) <?php wp_nav_menu( array( ‘theme_location’ => ‘secondary’ ) ); ?>
This will display your secondary menu however you will have to make your own CSS to match it your requirements.
Hope it helps