You accrue holiday days and holiday pay over your normal hours. The amount of normal hours are the hours which are in your CAO of your employer. Do you work more than these set hours? This will count as overtime. You do not accrue holiday days or holiday pay over your overtime hours.
For example: The CAO mentions that 40 hours per week are your normal hours. Do you work more than these 40 hours? Above the 40 hours per week, you will receive 130% overtime pay. You worked from Monday until Friday 43 hours. This indicates that 3 hours will be 130% overtime pay.