Customize SAP R/3 for SAP BW

SAP R/3 (OLTP) system needs to be customized so that data can be extracted in SAP BW. To extract data, one needs to activate the standard business content. For each application (e.g. SD, MM, etc.), there are data sources for extracting Master and Transactional data.

1) Log on to SAP R/3 system
2) Execute transaction SBIW
3) Go to 'Business Content DataSources'
4) Click 'Transfer Application Component Hierarchy'

5) In the confirm prompt: 'Do you want content application Transfer Component Hierarchy', press 'Yes'
6) Confirmation message will appear realted to transfer component hierarchy
7) Repeat step 2 & 3, click 'Business Content DataSources' 

Data Sources are extraction structure. They have list of fields. They are classified as Master Data Sources and Transactional Data Sources. Master data sources are divided in Attributes, Texts and Hierarchies.
8) Select the SAP Application Component, mark the data source and select Activate Data Source