Then update your app to apply your modification. (how to update app configurations)
Open browser again, see result:
Buttons menu is handled by Template service, you can get template service from anywhere by using
Phpfox::getLib('template'), within controller, service you can invoke method template() to get the Template service.
$template->menu('Add To Do', $this->url()->makeUrl('/to-do-list/add'));
Click on ADD TO DO, a not found page will be shown, The next chapter will guide you how to
create new controller to handle Add process, show input form about to do list task, store item to database.