The registration deadline can be set for each category. Select "Categories" in the left navigation of the event and change the date in the "Deadline" column of the desired category.
If the ticketing is activated, the registration deadline can also be controlled by the availability of the tickets. Select "Ticket types" in the left column and then click on the green pen button to edit the desired ticket.
In the window that appears, you can change the period of the ticket availability. To finish, always click "Save" at the bottom right.