Payroll >> Select a client >> Manage Payroll >> Additional >>

Alternatively, please click on this link to be redirected to the page

Once you click on the above link you will be redirected to the page below: 

On the page, click on the action button, then edit

This step is the same for SMP / SAP / SPP. This can be toggled on the leave type shown on the screen below in blue

Once this is clicked, the following popup will appear: 

On this popup screen when you click save, it will automatically update the SMP / SAP / SPP rates in payroll.