Most programs are either command driven in which you press a certain key or move a pointer to a certain area of the screen to do something, or they are menu driven in which case the computer gives you a number of choices and after you choose one of these gives you some additional choices or asks you a question or two before carrying out your command. Generally, for instance, word processing is command driven, and accounting programs are menu driven. Now for a few words about the mouse and the keyboard. Generally the mouse is a pointing device in which a command is chosen by rolling the mouse device over the table top until a pointer on the screen is on, or points to, a selected command. A button on the mouse, usually the left button, is then pressed to select that command.
Most mice have two or three buttons.
The right button, if used by the program, is usually used to cancel a command, although it can have other uses. The keys on the keyboard have different uses in different programs also. A few general rules can be stated however. The F or function keys have various or no functions as defined in the program being executed. Often the F1 key is used as a general help key.