You have just bought a linksys router(e.g. WRT54G, WRT54GS,BEFSR41, etc.) and you want it to connect to your modem. How can you do that? It's simple! Connecting linksys router to your modem will just take 2 minutes of your time! Just follow this steps:

HOW TO CONNECT LINKSYS ROUTER TO A MODEM

1. Using an Ethernet cable, connect one end to the Ethernet port of your modem and the other end to the "Internet"/WAN of the Linksys router. (NOTE:Look at the back of the router, there is a label named "INTERNET" port.)
2. Using another Ethernet cable, connect one end to one of the Ethernet/LAN ports of the Linksys router and the other end to the Ethernet/LAN port of your PC. (NOTE: At the back of the Linksys router, there are numbered ports like 1,2,3,4. Those are the Ethernet ports)
3. Make sure the power adapter of your router is plugged to a power outlet.