Now that we've understood the types in the business network in natural language, let's see how they are defined technically. On the left-hand side of the Playground, select Model File.

 In this business network, there is only one model file that defines the participants, assets, transactions, and events. In a bigger application, we'd keep the information from different organizations in their own files, and often in their own namespace. It allows them to be kept separate but brought together when necessary. Let's see how namespaces work.