Start Page
The Start Page is used for easy access to the diagrams recently opened and allows direct access to the command for creating a new diagram..
Recently Used Diagrams
The Start Page allows easy access to the diagrams recently opened,
You can open the diagram by double-clicking on it or selecting it and pressing [Enter].
Create a new diagram
You can click on the Create a new diagram on the Start Page to access the Start>New>New Diagram command. The overview of the diagram types that can be created appears. Click on the diagram type you want to create a diagram. A dialog then appears where you can control your model structure.
Open an existing diagram in the model
If you had not opened any diagrams in the model yet, you can jump directly to the Diagrams tool window view to open an existing diagram. To do this, click on Open an existing diagram in the model. Click on the diagram type's expander 
in the Diagrams tool window view of the diagram you want to open.
You can open the diagram by double-clicking on it or selecting it and pressing [Enter].