Wordpress Menu Usages

<!-------------------------------------------------------------------------------------------------------------------------->
//This code have to use in functions.php to registered menu
/******This code for registration for wp menu**********/
    function wpj_register_menu() {
         if (function_exists('register_nav_menu')) {
            register_nav_menu( 'top_main_menu', __( 'Main Menu', 'brightpage' ) ); // Here (wpj-main-menu) is unique id &  Main Menu is display name

            // Registared Another Menu
        }
    }
add_action('init', 'wpj_register_menu');
<!---------------------------------------------------------------------------------------------------------------------------->

<!------------------------------------------------------------------------------------------------------------------------->
 //This code have to use instead of ul li
              <?php
                if (function_exists('wp_nav_menu')) {
                 wp_nav_menu(array(
                 'theme_location'  => 'top_main_menu', // this id from functions.php
                'menu'            => '',
                'container'       => 'div',
                'container_class' => '', // this class is of before <ul> that is class of div
                'container_id'    => '', // this id is of before <ul> that is id of div
                'menu_class'      => 'menu', // this class is of <ul></ul>
                'menu_id'         => '',  // this id is of <ul></ul>
                'echo'            => true,
                'fallback_cb'     => 'wp_page_menu',
                'before'          => '',
                'after'           => '',
                'link_before'     => '',
                'link_after'      => '',
                'items_wrap'      => '<ul id="%1$s" class="%2$s">%3$s</ul>',
                'depth'           => 0,
                'walker'          => ''


                 ));
                }
                else {
                 wpj_default_menu();
                }
                ?>
<!------------------------------------------------------------------------------------------------------------------------->


This is wordpress source link:https://codex.wordpress.org/Function_Reference/wp_nav_menu