After you specify information for the parent object in the object profile, you can add child objects to the profile.

On the Source Record page, scroll down until you see Add child_type, where child_type is the type of child object you want to add (for example, Add Address).
Click Add child_type.
The page changes to display the fields associated with that child object type.
Fill in any open fields for the child object.
Click Save child_type.
Repeat the above steps for each child object to add.
Continue to Step 5: Save the Object Profile.