Depending on the scenario, if you want to onboard all or a single (eligble) External Reservation Unit for a given C4C-App connection, then you should either use the preparation action on the C4C-App connection (all) or on the External Reservation Unit (single).

Executing this action will display a pop-up to the user to provide a period for which the onboarding has to take place. This period can have a maximum range of 2 years (limitation by Microsoft Graph API).

The preparation of the onboarding items uses Planon's Event Connector to distribute the processing load, hence verify that all inbound messages related to the onboarding are processed before proceeding to the next step.