Register / display navigation menu

To register a menu :

add_action( 'init', 'dev__register_menu' );

function dev__register_menu() {

	register_nav_menus(array(
		'primary' => __( 'Primary Navigation', 'dev' ),
		'secondary' => __( 'Secondary Navigation', 'dev' ),
	));
}

To display a menu :

$args = array(
		'menu'			=> int | string | WP_term ,
		'echo'			=> false,
		'item_spacing'	=> 'discard'
	);
$menu = wp_nav_menu( $args );

echo $menu;

Sources :

• https://developer.wordpress.org/reference/functions/wp_nav_menu/
• https://developer.wordpress.org/reference/functions/register_nav_menus/