If you initially set your event up as either general admission (Space) or allocated seating (Seat), you will have the option to change the event to table seating.
To do so:
From the left menu, click Dashboard
Under Manage events overview, click the name of your event
From the left menu, click Sections, under Allocation
Click Add New Section, then click Next
Give the section a name eg. Tables, then click Next
Select Tables for Allocation Type, and enter in the number of tables you will have at your event and the number of seats at each table
Click Create Section, then Finish
Locate the original section that was on your event, select it by placing a tick in the box
Click Remove Section
If you have already taken bookings on your event, you will not be able to remove the event's original Section/s. It is recommended that you either Move those bookings over to the new section then remove the section, or change the Status of that section to Hidden.