This document provides instructions for paying self-assessment tax in SAP FI. It outlines the key steps which are: 1) Calculating the self-assessment tax amount manually outside of SAP 2) Paying the tax through a non-SAP process 3) Recording the outgoing payment in SAP using transaction code F029 4) Updating the status of the self-assessment tax payment in SAP by entering details like the year, acknowledgement number, date and status using transaction code ZFIE090.