Simulink is not a standalone tool, but lies on MATLAB's shoulders; it's almost impossible to use Simulink without keeping an eye on MATLAB's main window, not to mention that you need to start MATLAB before even opening a model.
Simulink inherits from MATLAB the current working folder, the workspace, and the path and uses MATLAB's Command Window to report errors, warnings, and notes.
The first time you open MATLAB, you should see the default main window view with the following sections:
The Workspace panel and the Command History panel on the right
The Command Window panel in the middle
The Current Folder panel with the folder contents on the left.
The current path is displayed above the three
An example is shown in the following screenshot: