The first of the DDD tactical patterns treated is Entities. The project team first leaned too heavily on these, overlooking the importance of designing with Value Objects when appropriate. This led to a discussion of how to avoid widespread overuse of Entities because of the undue influence of databases and persistence frameworks.
Once you are familiar with ways to distinguish their proper use, you see lots of examples of how to design Entities well. How do we express the Ubiquitous Language with an Entity? How are Entities tested, implemented, and persisted? You are stepped through how-to guidance for each of these.