То?
use Carbon_Fields\Container;
use Carbon_Fields\Field;
add_action( 'carbon_fields_register_fields', 'crb_attach_theme_options' );
function crb_attach_theme_options() {
$elemets_labels = array(
'plural_name' => 'Элементы', //entries
'singular_name' => 'Элемент', //entry
);
Container::make( 'theme_options', 'Дополнительные настройки' )
->add_fields(array(
Field::make( 'complex', 'crb_elemets' )
->setup_labels( $elemets_labels )
->add_fields( array( /* ... */ ) )
));
}
https://docs.carbonfields.net/#/fields/complex