For a contact page the norm is to have the form submit to itself, so you would set the action to the same page the form is on. You can then add in your Universal Email server behavior and set the redirect to go to the next page, like a thank you page.
When you press the submit button the page will submit to itself and the server validations will run. Once the inputs have been validated the Universal Email server behavior will run and send out the information. At the end of this server behavior the user will be redirected to the page you specify, like the thank you page.
When it comes to crafting the email message you can choose to create a new file for the message or create one with the DW button in the UE interface. If you make your own you would go to Bindings > Form Data to select the form page. With the bindings from the form page available you can drag and drop these onto the page where you would like to see them in the email.