bojinet

Hi all-

I'm hoping that I can find some help here. I have a wireless network set up using a Linksys G router, and am hoping to extend the range with a second Linksys router I have found. I am planning on connecting the two directly to each other. I have read what forum posts there have been here on what my steps for configuring the second router to do this would be, but I'm still a little lost.
Do both routers have to be powered on as I'm configuring the second router with a different IP Address? Do I have to be able to connect to the internet while setting the new IP Address?
I really know very little about this sort of stuff, so if someone would be willing to assume I know nothing and walk me through it, I would be very grateful.
Thanks so much in adance for any advice or information.