System/Assemby
The System/Assembly panel allows you to add new systems and assemblies to your model, modify attachments, and set initial conditions and options for systems and assemblies.
Systems and assemblies can be selected from the Project Browser. The Project Browser context menu is used to turn the currently-selected system or analysis on or off. When a system or assembly is turned off, it is dimmed in the browser, and is turned off in the modeling window.
Refer to Container Entities to learn more about systems and assemblies.