Once that is done, try to navigate to 192.168.1.1. You should be prompted to login, as stated by John, the default credentials are blank username with admin as the password. If you get a 404 error you likely aren't connected properly or the router is toast.
I didn't get a 404 error, but I entered the ip ,and it asked for a subnet, it filled that in automatically I exited everything, but I'm still not getting an Internet connection through ethernet or wireless. (i tried getting connection through airport on the mac and ethernet gets nothing too.)
Let me ask you something. What is your IP of the modem? If IP of modem and router are interfering, you won't get internet. What brand and model of modem do you have?