Once the Calendar has been created, you can update the Takt Time and Percent Capacity to add or remove Total Slots/Total Units. 

In the below example, the takt time at 100% capacity is set to 10 seconds, resulting in 16452 units over the time period. 

In this next example, the same calendar is used, but the Takt Time has been changed to 55 seconds at 75% capacity, resulting in 2232 units out of a possible 2982 potential units (slots).