For any Onepager you have the option to change what happens after a user signs up to your Onepager which by default is to stay on the page to make tweaks or grab the Share url.
You have the option redirect to any URL you want after a user signs up.
To add a Website URL for redirection you must go to the Settings tab inside any Onepager. You will find the "Advanced Options" button and this will open more options available to you.
The user will see a "redirecting" screen like the screenshot below before being sent to your URL.
The signed up user can go back to the OnePager at any time and make changes. The redirection process will only happen once immediately after signing up.