The form's data will post to the page you have specified as the action in the Form Builder interface. This is probably the thankyou.php page that you referenced. All of the data from the form should be available to you on this page. If you would like to make use of the bindings for it you should go to Bindings + Form Data, then select the page with the form on it. This will make the forms values available to you from this bindings tab. You can then drag and drop them where you need them.