The Pro-Rata/Fixed Entitlements area in an Employee Profile - Entitlements will determined how the leave will be generated.
A reminder that only payslip items that have been classed as Normal will generate entitlements on the hours for Pro-Rata
To change this setting navigate to Menu > Settings > Employees > click edit for the applicable employee > Employee Profile, under Entitlements - Pro-Rate/Fixed Entitlements.