Get submenu items from a WP menu based on parent or sibling WordPress

Firoja_Imtosupport answers:

Hi,

Please refer to below links:
http://christianvarga.com/how-to-get-submenu-items-from-a-wordpress-menu-based-on-parent-or-sibling/
https://gist.github.com/levymetal/5547605
https://www.minddevelopmentanddesign.com/blog/showing-current-pages-parents-sub-menu-items-custom-nav-menu-wordpress/