I made a custom nav bar.

The nav bar functions are called in header.php – search for

$args = array('theme_location'=>'avia2', 'fallback_cb' => '', 'container'=>'', 'echo' =>false);

$nav  = wp_nav_menu($args);

echo $nav;

(small nav bar at the top) or

echo "<div class='main_menu' data-selectname='".__('Select a page','avia_framework')."'>";

$args = array('theme_location'=>'avia', 'fallback_cb' => 'avia_fallback_menu', 'walker' => new avia_responsive_mega_menu());

wp_nav_menu($args);

(main menu nav bar).