how we can navigate wordpress to navigate a php file code example

Example 1: how make custom menu in wordpress

function wpb_custom_new_menu() {
  register_nav_menus(
    array(
      'my-custom-menu' => __( 'My Custom Menu' ),
      'extra-menu' => __( 'Extra Menu' )
    )
  );
}
add_action( 'init', 'wpb_custom_new_menu' );

Example 2: wordpress add menu frontend

wp_nav_menu(
array('menu' => "Menu 1") // Where 'Menu 1' is the Menu name or menu ID
);