Wizard can create diagrams quickly to start game commenting. However when making stylish commented game, diagrams often need some adjustment.
Diagram start can be seen in game tree in bottom right corner. There should symbol present indocating that diagram is there.
New diagram is added using command Insert > New Diagram. This show dialog, where you can define details of new diagram.
When you havefinished changes to diagram dialog, press OK button to store new diagram, or press cancel to abandon diagram. After adding diagram you can see it in game tree.