Payroll Processing Menu -> Maintain Payroll Transactions -> Maintain Employee Payroll Transactions (KE0066) -> Enter the Employee Number (as shown below)

Select New -> This will bring up the box shown below

Use the Look Up icon -> Select OK -> This will bring you to the Payroll Transactions screen (KE0063)

In the screen above tab through the fields until you reach the sections starting with Pay Code -> Use the Look Up icon

*The Look Up icon will provide a list of the employee pay lines, if there is only one pay line then the system will automatically pull it in for you.
Select Done -> Select OK to close out of it to add the employees pay line.