1. Locate the item that is to own the Activity, that is, an Activity, Actor, Basic Type, Class, Interface, Model, Package, Operation, Type Definition and Use Case.
2. Right-click the owning item.
3. Point to New, and then click Activity.
or
Point to New, point to UML, point to Behavior, and then click Activity.
4. Type the name of the Activity, and then press the Enter key.