Thank You Pages within Unbounce:
Create a variation of your landing page… build it out with any “thank you” page copy, design, analytics, etc that you want. Save it. Before you “re-publish” give it a 1% weight.
This will make the page viewable to the public.
Now go back and give it a 0% weight. This will take the page “out of multi variant testing”, but you can still access it by browsing to the page directly.
Where “variant”.html is it will be the variant letter… so b, c, e etc for example.
Now within your landing page where the form is make the confirmation dropdown say “goto another web page”, and for URL paste your thank you page URL.