i do i know when i have a new submission?

You can set up email notifications to be sent when forms are submitted.  These are our guides on setting up email notifications.  The first is on setting up notifications sent to you:

http://www.jotform.com/help/25-Setting-Up-Email-Notifications

The second is how to setup notifications to your users:

http://www.jotform.com/help/26-Creating-a-Form-Autoresponder

Data will also be available in your JotForm account:

https://www.jotform.com/help/269-How-to-view-Submissions