How do I set up my Linksys Wireless Router?

I cant set up my wireless router. I have a Linksys WRT54GS Router and a Motorla 2210 modem (I think thats the problem). When I connect my modem to my router and try to set up the wireless network, it says it’s set up but theres no active internet connection. I’ve tried to bridge the modem and it doesnt help at all. Help…