How do you use a simple wire tester?

Excuse me, could you please elaborate on how one would go about using a simple wire tester? I understand it's a tool used to check the continuity of electrical wires, but I'm not quite sure of the specific steps involved. Do you begin by turning the tester on, and then connecting the probes to the wires you wish to test? Also, what sort of indicators does the tester provide to show whether the wires are in good working order? I'd appreciate any clarification you could provide.