The mouse is one of two primary input devices in Windows—the other, of course, being the keyboard. Moving the mouse on your physical desk controls the motion of the mouse pointer on your screen. By moving the mouse pointer over an icon, control, or option and then clicking, you can select an item, open or move a file, run a program, or throw something away, for example.
A mouse has a left and a right button. You’ll use the left button for most actions, but skillful use of the right button is a key to working quickly.