|unfortunately the advice is missing major parts of the how to.|
You connect to the modem /router and note your ip address subnet
You then connect to the linksys router.
You logon to the router and change the gateway ip to be a ip in the first routers subnet. Lets say router1 has 192.168.1.1 for gateway. You set the linksys to 192.168.1.2 so you can later admin it. You disable its dhcp server. Save the config and exit.
Next you connect the main router to the linksys using a crossover cable connecting lan port to lan port. Note: you do not use the linksys wan port.
Then connect wired to your linksys and you should get a ip from router1 with internet and lan access.
You may want to further config the linksys wireless. You would access the linksys by the ip you set for gateway.
Answers are only as good as the information you provide.
How to properly post a question:
Sorry no tech support via PM's