This 12d Model Webinar video below will show details about Attributes, what they are and how to use them. Detailed in the webinar are Project attributes and String attributes.
Super Strings in 12d aren’t limited to Attributes for the entire string. Each Segment and Vertex can also have individual Attributes.
Project Attributes can be used in Snippets. For example, pavement details. When the Project Attributes are edited/updated, the changes are automatically applied during an MTF recalc.