Next Button in MCQ

I have several multiple-choice questions on a quiz page. I've also embedded an audio player on the page.

When I preview the page, I get the following behaviour:
1. When I answer a question and click submit, the page automatically jumps to the next question.
2. The "next" button is always greyed out and does not seem to have a function.

The simplest solution for me would be to remove the "next" button. How can I do this?

Ideally, I would like to change the "next" button into a back button so that users can review their answers. Is this possible?

Thank you!

Ok. I've got it. If you enable "feedback" the functionality I want words.