create custom post wordpress

follow the below link and its step to make the custom post menu and custom post feature.

https://www.codexworld.com/wordpress-custom-post-types-without-plugin/

display dropdown menu on wordpress pages dynamic code

<?php wp_nav_menu( array(
'menu'           => 'menu-name', // Do not fall back to first non-empty menu.
'theme_location' => '__no_such_location',
'fallback_cb'    => false // Do not fall back to wp_page_menu()
) ); ?>