You can create a Decision Node through an Activity Diagram or a Modeler pane.
To create a decision node through an activity diagram:
1. On the Activity Diagram toolbar, click the Decision Node button, and then on the Activity Diagram click in free space or within an Activity Partition, Interruptible Activity Region or Structured Activity Node.
2. Type the name of the Decision Node, and then press the Enter key.
To create a decision node through a Modeler pane:
1. In a Modeler pane, right-click the Activity or Structure Activity Node that is to own the Decision Node, point to New, point to Control Node, and then click Decision Node.
2. Type the name of the Decision Node, and then press the Enter key.