You can create an instance from the Model or Package, or from the Class, Data Type, Interface or Signal that is going to be the classifier of the Instance.
To create an instance from the model or a package:
1. In the Packages pane, right-click the Model or Package that is to own the Object Diagram, point to New, point to UML, point to Structure, and then click Instance.
2. Type then name of the Instance, and then on the keyboard press the Ente key.
To create an instance from a class, data type, interface or signal that is to be the classifier of the instance:
1. In the Packages pane, right-click the Class, Data Type, Interface or Signal that is to be the type of the Instance, point to New, and then click Instance.
2. Open the Instance's Property Pages and name the Instance as required.