The Domain Model is a set of classes of things within the scope of your project and the relationships between them. The Domain Model describes the data in your knowledge graph. Creating a Domain Model is the first step in building your graph. You can evolve the model later, so don't worry if it is not complete the first time.
Domain Modelling
The Domain Model tool allows you to rapidly build an ontology. Start by adding classes to the canvas representing the types of entities in your domain, using the Add Class button at the bottom right:
Subclassing
The round + button allows you to make the selected class a subclass, simply by dragging it up to the parent class. In this case we drag from Article to CreativeWork:
Relationships
With the + button, you can make a relationship between existing classes. In the example, we create the author relationship by dragging from CreativeWork to Person.
New properties
If you want to create a property, click the square + button. Dragging and releasing the arrow to a space on the canvas will open an editor on the right-hand side, where you can then set the property's data type and attributes.
Documentation
The Add Note button at the bottom right of the canvas allows you to add explanatory notes to your model. These appear on the model canvas but have no effect on the model itself.
Saving the model
Once you are finished with your current amendments, hit Save Model.
A warning next to the button indicates errors in the model, which will need to be fixed before you can proceed.
Clicking on the warning indicates what/where the errors are.