This is a simple network diagram that most people have in their homes for instance. A basic modem connection to a WiFi router from which you connect all your other devices to get online.
This setup is usually for Offices and other business setups. The added component here is the Switcher which allows you to ADD more computers to the network setup.
Also note that you have HardWire connections to help secure your setup better.
Also note that you have HardWire connections to help secure your setup better.