Had someone submit for our event and it does not show they submitted

What do I need to do to activate or enable this form so people can click on it from FB to register

If you see nothing, that means no submissions is actually made in the form. If you are administering a Facebook fan page, you can add the form there as a tab. Here's how: 

http://www.jotform.com/help/22-Adding-Form-to-Facebook-Pages

You can also embed the form using custom iframe app:

http://www.jotform.com/help/82-Adding-Form-to-Facebook-Custom-iFrame-App-