You can specify a set of internal actions on an atomic or decomposed state from the Actions tab in the state property sheet. They represent actions performed within the scope of the state when some events occur. You can create and define the properties of the action from the Actions tab, or double-click the arrow at the beginning of a line to display the action property sheet.
You can open the Actions tab by right clicking the state symbol in the diagram, and selecting Actions from the contextual menu.
For more information on actions, see Actions (OOM).