Go to Team -> Click the team member

Under Holiday Allocation, click New

Enter the start date as the date holiday allowance renews

Then enter either the days in their allowance and the average number of hours worked in a day OR enter the total number of hours in their allowance

Click Create

Absences entered as holidays will now be tracked

You can click on the date range for this holiday period to see how much holiday has been used, and what is left