1. In the event dashboard click on the "Registration" option from the sidebar.

2. Click on the "Manage Tickets" options under Ticketing.

3. Click on the "Add" option.

4. A page will open up where you can input the ticket information, such as the name of the ticket, description, etc,.

5. You can choose whether the ticket has to be a paid ticket or a free ticket. Simply uncheck the box beside "Is Paid" if you want the ticket to be free.

6. Expand the "Advanced" section.

7. To make this ticket available only for a certain period, please choose the relevant "Valid From" and "Valid Till" dates from the drop-down menu.

8. Click the "Select date & time" field.

9. Select the relevant date and time from the calendar prompt shown, and click on the confirmation icon provided below.

10. Now, choose the "Valid Till" option to set up a time and date until when the ticket should be valid and available for attendees to purchase.

11. Click the "Select date & time" field.

12. Select the relevant date and time from the calendar prompt shown, and click on the confirmation icon provided below.

13. Click "Save" to update the changes.

Tip: Now, this particular ticket will be available only from the selected "Valid From" to "Valid Till" date. Once the valid till date has passed, the ticket will expire.