Topic: Need other menu below the main menu

Hi! I¡m working with the Royal Theme and the client need a secondary menu always visible for premium contents.

I’d created a child theme, and inserted this lines to functions.php in royal-child template:

function extra_setup() {
register_nav_menu (‘premium-menu’, __( ‘Premium Menu’, ‘Este es el menu premium’ ));
}
add_action( ‘after_setup_theme’, ‘register_premium_menu’ );

Then. I’d add this line on the bottom of the Header.php in royal-child template, after the line <?php get_template_part(‘headers/header-structure’, $hstrucutre); ?>:

<div class=”premium-menu”>
<?php wp_nav_menu( array( ‘theme_location’ => ‘premium-menu’, ‘menu_id’ => ‘premium-menu’ ) ); ?>
</div>

That shows the menu below the actual one, but I need to style and also this menu need to appear in mobile version. How can do that? what it’s the best way to do full editable as the main menu?
I can manage the elements of the menu on the menu area of wordpress, but I need this menu responsive for mobile and tablets also.

NOTE: below this new menu,in the site there is actually a revolution slider that I’d turned into menu, using the revolution slider place on top of pages, not in header. I need the new submenu i header area.

thanks in advance