Instructions
Measure the distance between the Xbox 360 and the Linksys BEFW11S4 router, and acquire an Ethernet cable of adequate length to connect the two together.
Connect one end of the Ethernet cable to the RJ45 network connector on the rear of the Xbox 360, and the other end to one of the four LAN ports on the back of the router.
Switch on both the Xbox 360 and the router. The router will automatically assign the Xbox 360 with an IP address that allows it to receive an Internet connection.
On the Xbox 360 dashboard, go to "Settings," followed by "Network," and click the "Text connection" button to check the Internet connection was successful.