How do timing networks work?
Your question is so general that it can only be answered in generalities. Assuming you are referring to lights that are turned on at specific times, there are several methods.  You can use a purely mechanical timer with cams that turn on switches that, then, turn on lights.  One step up is an electrical timer run by a synchronous motor that also turns on lights at specific times using relays or switches.  For more versatility, a microprocessor can be programmed to behave as a timer and to activate mechanical or solid state relays to turn on lights at programmable times and durations. Light sensors can be added to this programmable timer to turn on lights only when it is dark.  Motion sensors will turn on lights when motion is detected.  There is no limit to what can be done with the proper sensors and programmable controllers.