CIN is used to calculate excise duty and VAT for sales and purchases based on industry requirements. It involves configurations across the FI, MM, and SD modules including maintaining master data like chapter IDs, customer and vendor excise details, and material-chapter combinations. The sales process is enhanced to calculate excise duty for various sales scenarios like sales from factory, depot, stock transfers, and returns. Pricing procedures need to be configured and condition techniques copied for the different excise duty types. Various scenarios and documents need to be reviewed and configurations set through IMG and checking with transaction code J1iLn.