To add a state to your DES, click the button corresponding to the type of state to add in the toolbox on the left:
Next click in the DES editor workspace where you wish to place the state. This will open the DES State Editor dialog box.
Enter the state name and alias in the text boxes. If you selected the wrong type of state you can change it by clicking the checkboxes for the initial and marked properties. Click OK and your new state will be added to the DES. You will notice your new state listed in the states pane.