I use the Broad band connection.To use the internet, It's connect to the computer directly, from the ISP said.
Then, I set up a router to share the internet . But then I can't get the internet. In router,the light of internet is light up and, lan connection light is also light up.
So , I put off the router and directly connect to the computer. Then it can use the internet.
Now, my problem is I can't share internet with others computers.
Then I ask others , they said me , it must put the setting to the router.
How should I put the setting to the router
Give me detail instructions clearly.

Without knowing what router you have its impossible to answer. What I would suggest you do is reconnect the router, making sure its connected properly. From broadband modem to WAN port, then connect PCs to LAN ports. Make sure the PCs are setup to obtain an IP automatically. If it still doesn't work, call the router tech support and have them walk you through the setup.

You just try to get your configuration of your existing computer [IP ADDRESS. SUBNET MASK, GATEWAY, and DNS] configure the same on your New Router. Change your PC IP setting to DHCP (it is not nessory all the internet connection can share to more than one computer- better you ask your ISP).