BuddyPress.org

There’s a plugin for this but might need the pro version depend on what you’re trying to achieve.

Here: https://wordpress.org/plugins/buddypress-custom-profile-menu/

If you prefer using codes from discussions, might try the links below

Creating sub nav
https://buddypress.org/support/topic/create-sub-nav-menu-item-in-profile/

BuddyPress Custom Nav and Page Template
https://buddypress.org/support/topic/buddypress-custom-nav-and-page-template-2/