To connect more than two computers with Ethernet, you will need a hub like this. Coax was once the more popular of the two, but today just about everyone uses Cat 5 because it is easier to configure. Cat 5 has a cable that looks a lot like a telephone cable. You run one cable to each computer, and each cable connects to a hub at the other end. The hub takes the signal from each computer and sends it to all of the other computers in your home.
Hubs come in several sizes, noted by the number of ports available to connect computers to the hub.
Most hubs are stackable. A stackable hub has a special port that can connect it to another hub to increase the capacity of your network. This type of cabling is designed to handle the 100-Mbps speed needed by Ethernet. You can buy Cat 5 cables in predetermined lengths with the connectors already attached. If you plan to install the Cat 5 cabling in the walls of your house, you can buy the cable in rolls, cut it to length and connect the cable to special RJ-45 wall boxes.