What form action method are you using? POST or GET?
If you are posting then you will set the value of the form on the second page to $_POST['ntu_date']
If you are getting then you will set the value of the form on the second page to $_GET['ntu_date']
The other thing you could do, if you want to store the values for future use within a multi-page form is post the form to itself, store the form values in session variables and then redirect to the next page. Then you can call on the session values whenever you need to.