When using relevant hourly rate to pay employees on a public holiday you need to select the appropriate number of hours for that day. For employees that work regular hours, the answer might be simple. But for casual employees and employees that work irregular hours, it might be more difficult to identify what is the correct number of hours to pay the employee.
Inside the information button, you are presented with information to better decide what the most appropriate hours are for the relevant public holiday.
More information can be found at the MBIE website at https://www.business.govt.nz/hiring-and-managing/handling-holidays-and-leave/public-holidays/