Of course, nothing happens with the submitted data in our tutorial. However, if this was a real world website, you should do one of the following:
1. Download or program a front end module that handles the form data and include it on this page.
2. Edit the form header (using module "form generator") and choose to send the form data via e-mail. Enter a working e-mail address and a subject and save the form. Then go back to the front end page and submit the form again. You should now receive the form data via e-mail.
By the way, the "Go back" link above is not a static link (of course) but a dynamic one. It was created using an "insert tag" called link::back. There are a few insert tags in Contao that help you include dynamic data.