The Domain Model becomes a shared language and framework for the team to communicate and make decisions. You use , a concept from DDD, to ensure that everyone on the team uses the same terminology.
You can find more information on Domain-Driven Design in Eric Evans' book, which is available in various formats, including PDF.
Within the Ordering context, you create a that represents the business concepts and rules. You identify key entities like Order, Product, and Customer. You also define Value Objects like Money and Address.