Linking items
You link items on a Concurrency Diagram with message flows. Message flows depict communication between tasks, concurrency primitives and classes. Events and operations are carried by message flows. Operation messages are attached to classes or items associated with classes.
To link items
1. On the Concurrency Diagram tab, click 
.
.2. Click the items you want to link. A message flow is added to the diagram to link the items.