The only address seen from the outside is the one given or assigned to the external router port. This makes setup of individual nodes easy to maintain. The major NOSs accepts DHCP for setup of IP addresses on nodes within the network. These IP addresses are usually set in the non-transmittable IP addressing scheme such as 192.168.1.1. Switches are smart hubs and understand the network addressing scheme to send network traffic directly from point to point.
Switches are much faster than hubs.
By now, it can be seen that the hardware side of network is no big deal. The components can be purchased off the shelf. The NIC drivers are easier to setup than in the past. There are advantages to networking more than one computer to leverage the use of resources. The number of printers, etc., can be reduced in a network through sharing.