How can we start the form over again after it has been submitted?

So you mean that you want to have your jotform sort of reset itself to go back to the empty form after seeing the thank you page when someone submits on it.

To do this simply get your forms url "https://www.jotform.com/51035300858954" and add it as a thank you page url to redirect them back to it again.

See this guide here https://www.jotform.com/help/38-Redirecting-Users-to-a-Different-Page for a more detailed explanation.