After all InDesign documents for a publication have been finalized and saved back to STEP, data about the mounted products and the pages on which they appear can be exported from the publication in order to generate an Alphabetical Index - XML file. This XML file format is used to create both types of indexes—the basic 'stock number' index and the more advanced 'alphabetical index.'
Details about this option can be found in the Exporting Index Data from STEP section of the Print Publisher documentation here.
The user interface for the mapping step of the Export Manager tool and the outbound integration endpoint tool are not exactly the same. For Export Manager, mapping is described in the Export Manager - Map Data topic here. For OIEPs, mapping is handled in the Output Templates section under the Format parameter as described in the OIEP - Event-Based - Output Templates Section topic (here) or the OIEP - Select Objects - Output Templates Section topic (here).
For more information about the additional wizard steps, refer to the Creating a Data Export topic (here) or the Creating an Outbound Integration Endpoint topic (here).
After mapping, most output options can be altered using transformations. For more information, refer to the Outbound Map Data - Transform topic here.