Hi @gabriels5091362 You can find an ERD of the built-in resources in ACS here: https://experienceleague.adobe.com/docs/campaign-standard/using/developing/about-custom-resources/data-model-best-practices.html?lang=en A data dictionary of the built-in resources can be found here... if you select 'Next...

Interestingly, within Adobe Campaign Standard, if you have a second dateTime field in your custom resource that does have an empty dateTime value, you can enrich this empty field as additional data, and update the destination field with this empty source field. This may not be possible for bulk data...