I think he's asking how to get into the setup page so he can change his password.
First, RTFM (Read the Fine Manual) that came with your router. If you don't have one, go to the company's website and under Support you should be able to d/l a copy in PDF format. That should give you the exact steps.
In general, "modern" routers have a web-interface setup page located at 192.168.0.1 or 192.168.1.1. Check your manual for the IP address. To enter this page you'll have to input the Adminstrator's userid and password, which are found in your manual (usually something like "Admin" and "1234", fer example). From there you can configure the router to your heart's content.
If the default IP address, user id, or password has already been changed and you don't know these you'll have to reset the router to factory default. There should be a small button on the back marked, "RESET" or "ZEROIZE" that you press with a ball point pen tip or paperclip wire, hold for 5 seconds, and release. This will flush all user-supplied settings and restore the unit to factory default.
Older routers use a Telnet command line interface to apply user settings. Also, these may not have a reset button and you'll have to reload the factory-default firmware (found on the disk that came with the router or can be d/l'd from their website). You'll REALLY need the manual to figure these out.
