If you need to have a reference form ID # for your records, you can locate this on each form that has been submitted.
Go to the school needed> dashboard> View details 
Check all three options to show all students.
Click on the student and view reg form.
Go to the bottom of page 1 and the Reg# will be listed on the form.
If you don't have access to the dashboard cards you can go to student tools>add new student> manage online registrations.