Establish a Root Data Extension
By default, the All Subscribers list of the email application is a root source of subscriber data for the email channel Contacts Model. You can create your own root source by creating a new Attribute Group and by defining a Data Extension as a root. A root Data Extension allows for a new source of subscriber information to be established. At a basic level, it allows subscribers that don't already exist in your All Subscribers list to be injected into an interaction. These Data Extensions must be sendable when you create them.
A root Data Extension must be set up as a One to One relationship from the Contact object in the Attribute Group. Upon setting up a One to One relationship linked to the Contacts object in Contact Builder, a checkbox will display in the editor to select your data extension as Root. When setting up this up, you'll want to set the Contact Key on the Contacts object up as linked to the Subscriber Key (or unique identifier for subscribers) within your Data Extension.
Link Data Extensions for Filtering
After linking your root Data Extension to the Contacts Model, you can link other Data Extensions to your root. This will allow you to implement more robust filtering options when creating entry events and decision splits within your interaction. If you don't link the Data Extensions you wish to use within the filters inside of your Attribute Group, the filters will not perform as expected.
Add your Root to the Channel Address Order
Whereas, adding a root Data Extension allows for a new subscriber to be injected into an Interaction, adding a root Data Extension to the channel address order allows for a new subscriber to be sent to. Once you have created your extension, you can add this to the channel address order by going to Contact Builder | Contacts Configuration.
Once you add the root to the Channel Address Order, you can change the ordinality of the root Data Extensions within it. Going from top to bottom, the system will check for that contact in the various sources in order to find their information.
Create an Event Source Data Extension
The Event Source Data Extension is the object that an interaction looks at for new records to act upon. Any new rows (added since the last fire event) within an Event Source Data Extension will be processed by an event when a fire event activity runs. The Event Source can be added to your Attribute Group, but does not have to be.
Note: The only stipulation is that if you want the records within the new rows to process, they must exist in at least one root Data Extension that has been established and added to the Channel Address Order, or already exist on the All Subscribers list.
Are you experiencing issues getting Contacts to inject into an interaction? We're here to help. Review common scenarios and how to troubleshoot them.