Creating an io flow
You can create an IO Flow as an IO Flow Link between two items, or as an IO Flow that is realized by an Association, Control Flow, Exception Handler or Object Flow.
To create an io flow link between two items (class diagram or object diagram):
1. On a Class Diagram or Object Diagram, ensure that the items you want to link through an IO Flow are shown.
2. On the Class Diagram tab, click the 
IO Flow Link button.
IO Flow Link button.3. Click the source item, and then click the target item.
The source and target items can be Actors, Classes, Data Types, Instances and Interfaces.
4. From the Select Object dialog, select or create the IO Item (conveyed classifier) for the IO Flow. The IO Item can be a Basic Type, Class, Data Type, Interface, Signal, Event or Type Definition.
5. Type the name of the IO Flow, and then press the Enter key.
To create an io flow link between two instances (sequence diagram):
1. On a Sequence Diagram, ensure that the instances you want to link through an IO Flow are shown.
2. On the Sequence Diagram tab, click the 
IO Flow button.
IO Flow button.3. Click the source Instance, and then click the target Instance.
4. From the popup menu, click New.
5. From the Select Object dialog, select or create the IO Item (conveyed classifier) for the IO Flow. The IO Item can be a Basic Type, Class, Data Type, Interface, Signal, Event or Type Definition.
6. Type the name of the IO Flow, and then press the Enter key.
To create an io flow that is realized by a link (activity diagram, class diagram or composite structure diagram):
1. On an Activity Diagram, Class Diagram or Composite Structure Diagram, ensure that the Association, Control Flow, Exception Handler or Object Flow is shown.
2. On the diagram tab, click the 
IO Flow Realization button.
IO Flow Realization button.3. On the diagram, click the Association, Control Flow, Exception Handler or Object Flow.
4. From the Select Object dialog, select or create the IO Item (conveyed classifier) for the IO Flow. The IO Item can be a Basic Type, Class, Data Type, Interface, Signal, Event or Type Definition.
5. From the popup menu, click the command for the required direction of the IO Flow.
6. Type the name of the IO Flow, and then press the Enter key.
Alternatively,
1. In a Modeler pane, locate the item that you want to use as the IO Item (conveyed classifier) of the IO Flow.
2. Drag the IO Item from the Modeler pane to the Association, Control Flow, Exception Handler or Object Flow on the diagram.
3. From the popup menu, click the command for the required direction of the IO Flow.