By default when a form is submitted the users see a confirmation message, you can however change the behaviour so that on submit of the form the user is redirected to a different URL.
To set this destination URL, when you are editing the form, in the right menu you will see a "Thanks Page" button that looks like this:
When you click on this it will show options for what "Thanks Page" behaviour you would like. Here you can change the behaviour to "Redirect to a different URL", and specify the URL that you would like people to be redirected to after they successfully have submitted the form.
