You're obviously using the form data to display the variables on the second page to the user. At the same time user hidden form variables to hide them in the HTML, and the submit button will submit those!
This is how it works:
Page 1 - Contains a normal form to capture data, action is page 2
Page 2 - Displays data for checking purposes. It also reproduces the form but uses hidden elements
eg <input type=hidden name='test' value='<?=$_POST['test']?>'>
This form action will be set to Page 3
Page 3 - Captures all the form data, compiles it into an email and sends it, and also displays a success message to the user!