Usually plugin and themes needs to add menus in the Administrator panel for provide access to screens. The best way is adding a menu section in the Administration menu that allows the user to access the screens.
There are some functions for manipulate the Administration Menu.
osc_add_admin_menu_page( __('Listing'),// menu title osc_admin_base_url(true).'?page=items',// menu url'items',// menu id'moderator'// capability) ;
osc_add_admin_submenu_page('items',// menu id __('Manage listings'),// submenu title osc_admin_base_url(true).'?page=items',// submenu url'items_manage',// submenu id'moderator'// capability) ;...