First, please check your spam email folder. If the confirmation is not in your spam folder, please log into your Submittable account (https://manager.submittable.com/login).
In your Submittable account, navigate to the My Submissions tab to see if your application is there. If it is, then you have successfully submitted.
If you do not see your application under the All Submissions tab, click on the Drafts tab. If your application is under the Drafts tab, then it has not been submitted. Click Continue to complete and submit your application.