How to Hide 6Storage Rentals Admin Menus

function plt_hide_6storage_rentals_menus() {
	//Hide "6Storage".
	remove_menu_page('six_storage_online_configuration_menu');
	//Hide "6Storage → 6Storage".
	remove_submenu_page('six_storage_online_configuration_menu', 'six_storage_online_configuration_menu');
	//Hide "6Storage → Settings".
	remove_submenu_page('six_storage_online_configuration_menu', 'six_storage_online_settings_menu');
	//Hide "6Storage → Leads".
	remove_submenu_page('six_storage_online_configuration_menu', 'six_storage_online_storage_option');
}

add_action('admin_menu', 'plt_hide_6storage_rentals_menus', 11);

Where do I put this code?