You want to calculate wage types /801 and /802.

The calculation rule XPPF is used to calculate the wage types /801 and /802, which are the gross and net pay for the current period. The operation XPPF calls the personnel calculation rules XPPO and XPP1, which perform the following steps:

XPPO: This rule calculates the gross pay (/801) by adding up all the wage types in the IT table that have the processing class 10 set to 1. The operation ADDWT&10 adds the wage types to the /801 wage type and stores it in the OT table. The operation ADDCU cumulates the /801 wage type in the CRT table.

XPP1: This rule calculates the net pay (/802) by subtracting the deductions from the gross pay. The operation SUBWT&11 subtracts the wage types in the IT table that have the processing class 11 set to 1 from the /801 wage type and stores the result in the /802 wage type in the OT table. The operation ADDCU cumulates the /802 wage type in the CRT table.

References = Payroll Schema, SAP Certified Application Associate – SAP HCM Payroll for SAP S/4HANA, SAP HCM Payroll for SAP S/4HANA - SAP Training Shop, Internal Tables for Payroll