The Mapping module is where the revenue and occupancy data (room nights, guest nights, covers, etc.) from the various source systems is imported to PMI. Usually there is very little maintenance of this module except in cases involving:

1. the first month of PMI usage.
2. change or upgrade of source systems.
3. changes in the general ledger (GL) chart of accounts.

What items or accounts do I need to map? 

All revenue, revenue corrections, and statistical accounts should be mapped in PMI. Statistical accounts are those related to occupied rooms and in-house guests, both actual and historical. Payment accounts, tips, VAT, deposits, commissions, and transfer codes should be ignored in PMI.