BuddyPress.org

It depends on what your plugin does, but in general, I would assume that BuddyPress plugins that have options a site admin can set would be listed as a submenu under the BuddyPress menu grouping.

In add_submenu_page( ), just make sure to set the first parameter to ‘bp-core.php’ if you want it to appear under the “BuddyPress” menu grouping. If you want the menu to instead appear under the “Site Admin” menu grouping, you would then set the first parameter to ‘wpmu-admin.php’.