Creating a Use Case Diagram

You can create a use case diagram in an existing OOM in any of the following ways:

Right-click the model in the Browser and select New > Use Case Diagram.
Right-click the background of any diagram and select Diagram > New Diagram > Use Case Diagram.

To create a new OOM with a use case diagram, select File > New Model, choose to create an object-oriented model from the Model type list, choose Use Case Diagram as the first diagram, and click OK.