You could open last year’s schedule and then do a File > SaveAs to a new name.

You can then navigate to the Tools and choose this item:

You would then go to the master calendar and right click on the calendar choosing to select all timeslots.

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If you are starting over on timeslots for the year, you can press the delete key and all timeslots will be gone.

If you want to simply move the (now unscheduled) timeslots to this year, use this menu item.