Limit entries in form with check boxes

I am making a form for people to register for a series of courses.  There will be 5 dates.  The dates only hold 4 people/4 applicants.  I want this to be on a first-come first-served basis.  Hence after the first 4 people have registered for the first date, I want this session to be closed to registration.  Everyone else will have to book for one of the other 4 dates.   How do I do this? 

Thank you. 

Edie 

You can use the Appointment Field for that and limit the available time lots to 4. Example:

Or you can use this alternative widget https://www.jotform.com/widgets/weekly-appointment-planner where you can define the 5 dates as an option and add available quantity in each of the dates.

If you need further assistance, let us know.