What must you do to ensure a schedule does not operate on a holiday?

Nothing. By default, the schedule will not operate on a holiday.

Program the holiday into a holiday group. Apply that holiday group to the schedule. Program the holiday mode of the applicable periods to 'Disabled on Holiday'.

Program the holiday into a holiday group. Apply that holiday group to the schedule. Program the holiday mode of the applicable periods to 'Enabled on Holiday'.

Program the holiday into a holiday group. Apply that holiday group to the schedule. Program the holiday mode of the applicable periods to 'Ignore Holiday'.