You can add a diagram to the currently opened diagram using the File > Add command. After you have added the diagram, some blocks and wires may overlap because of this operation; use the mouse and Edit menu commands to reposition them appropriately.
To add block diagrams
1. Open the diagram into which you want to add another diagram.
2. Choose File > Add.
3. In the File Name box, type or select the name of the diagram you want to add. If you do not see the diagram you want to add, select a new drive or directory.
4. Click OK, or press ENTER.
An empty rectangular box appears that represents the diagram. The pointer is anchored to the box.
5. Move the box to where you want the diagram added.
6. Click the mouse.