Borrowed from a quick Google/Bing/Almost any search engine search.
"To connect more than one computer to the Internet, you need a router. A router allows you to connect several computers to each other and to the Internet. The router sits between your computers and the modem provided by your ISP. You connect the router to the modem, and then connect all your computers to the router.
Diagram showing how a desktop computer and a laptop access the Internet through a wired connection
To connect a router and multiple computers to the Internet
Contact an Internet service provider (ISP) and have them configure an Internet connection to your home. If possible, have the ISP place the modem in the room with your primary computer.
If you currently have a computer connected directly to your modem: Unplug the network cable from the back of your computer, and plug it into the port labeled Internet, WAN, or WLAN on the back of your router.
If you don't currently have your computer connected to the Internet: Plug one end of a network cable (included with your router) into your modem, and the other end of the network cable into the Internet, WAN, or WLAN port on your router.
Plug in your router. After a minute or two, the Internet, WAN, or WLAN light on your router should light up, indicating that it has successfully connected to your modem. "
Tried to clean up some, picts from other site didn't paste through.