To do this go to: Admin > Personnel >Manage Staff Attendance
Enter the date range for one of your holidays. Click the tick box to "include holidays" and click view register.
Once the register is visible all staff are selected on the right hand side, in here you can uncheck the staff who do work the holidays and at the bottom select the holiday code from the dropdown and click onto fill spaces.
Please be aware this will only fill in where attendance codes aren’t already entered so if a pattern or present codes are visible in this period you may need to remove the codes before filling the spaces.