BeOS windows and menus look and feel a lot like those of other operating systems. Because of this, most users won't have any trouble with the BeOS graphic interface. Nonetheless, the Windows and Menus sections look at the different parts of BeOS windows and menus, and describes the techniques that you use to manipulate them.
Similarly, the way in which BeOS interprets your actions on the mouse and keyboard shouldn't cause any confusion. The Mouse section tells you how to simulate a three-button mouse if your mouse only has one button. The Keyboard section describes alternate ways for generating special characters (Alt, Control, Command, etc.) for keyboards that don't naturally provide these characters. It also tells you how to set the "shortcut key" (the key that's used in menu shortcuts).
The Shortcuts section provides lists of keyboard and mouse shortcuts are interpreted by the desktop, by Tracker, and by other applications.