To be able to run payroll for your employees, you must switch to the "Settlement" tab.
Payroll accounting and calculations are based on the data entered in the employee's wage information.
You then have the option of changing the payroll directly by clicking on the desired employee again and then on "Details" in the right-hand window:
You will then be redirected to the settlement overview and now have the option of adding new components by clicking on "Add payroll type":
To change a payroll type directly in the employee's payroll data, you can click on their name in the settlement to access their personnel master data: