This document provides instructions for implementing a Business Add-In (BAdI) within an enhancement project (CMOD) in SAP. It explains how to create a BAdI definition, add a BAdI hook to an existing enhancement, and develop two separate BAdI implementations. This allows custom functionality to be added to an enhancement in a modular way without limitations of CMOD. The example demonstrates creating a popup dialog for each BAdI implementation to be triggered when changing the time zone of a company address.