If First Purchaser is enabled the top of the menu will show Third Party Maintenance.
Third Party Maintenance is meant for Run Statements only. It associates owners in Sub-Table 101 with properties for which they are to receive Run Statement information. The owners should already be setup through other modules. Simply use the Reported Properties tab to add the corresponding properties.
NOTE: If First Purchaser is not enabled, the menu will show it as Interest Owner Maintenance. Please see OGP Third Party for more information since this menu will have different uses and behaviors.