To add a new scheduled override, click the + button in the Override Conditions section of the time switch configuration.
Provide a name for your override, then select the date range the override will apply on (note these dates are inclusive). From the drop-down, select where any callers should be sent during this override, then select your start time. If you're only adding a single rule, you can leave this at 12AM.
In this example, all callers reaching the time switch between 12AM on the 10th April and 11.59PM on the 13th April will be routed to a message announcing the business is closed.