How do I look up all submission?

You may check the submissions of a form from the submissions view.

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

You may also try generating reports for the submissions received for your form.

https://www.jotform.com/help/326-How-To-Create-Form-Reports-in-JotForm

Hope this information helps!