How can I start a new form after submit instead of the thank you page?

Thank you for contacting us. You can use the "Redirect to external link" option of the Thank You page, where you can put the link of the form.

Guide: https://www.jotform.com/help/211-Setting-up-the-Thank-You-Page

Please open a new forum thread if you need anything else, we will be glad to assist you.