Answers:
First, determine the address of your router so that you can type it into your net browser and access it. I'm assuming that you're using Windows XP here:
Go to Start > Run and type "cmd", and hit enter. You'll see a black console come up. Type "ipconfig" and hit Enter. Now, you will see the IP address for "Default Gateway". It will be a number close to 192.168.0.1.
Type the number you see, beside the period, into your browser, as if it be a network page address, similar to this:
http://192.168.0.1 (except money the number to yours)
Hit enter.
Now you can configure your router.
Configurations rise and fall for respectively router.