If you haven’t already, try our Statutory Holiday pay calculator for free here. 

And here's a quick walkthrough: 

To add this to your payroll, start your pay run as usual.

On the Salaries or Timesheets tabs, approve the employees' regular hours.

A. To add the statutory holiday pay, click the + icon to the far right of the desired employee.

B. Select statutory holiday from the list of earning types.

C. Set the rate to 0.
D. Enter the hours worked on the holiday if applicable. 
D(2). Or, if the employee didn't work on the stat holiday, enter the hours the employee would have typically worked. If you're unsure what that figure is, take the total our stat holiday calculator provided and divide it by the employee's hourly rate.
E. Enter the amount calculated using our stat holiday calculator.
F. Click Add and Submit, and it will be added to your payroll. Repeat this step for the rest of your employees and continue on with your pay run per your normal process.