I suggest you go to the website of your router manufacturer and download the manual for the router. Then find the specific instructions to enter whichever password you are talking about.
Most wireless routers have either three or four different passwords – the configuration password, the password that forms part of the credentials along with the username to allow connection to the ISP, and the pass phrase for each of one or two wireless networks.
Without knowing what router you have, I doubt whether you will get a more specific answer.
you connect a pc using a lan cable. you look at the label on the router which should tell you the login. you open your browser and type in the ip/ login eg 192.168.1.1 or www.routerlogin.net ie whatever the router label says. and then it displays the login screen. after that you configure the router using the main page wizard. then you can think about Wifi signals and Passkey values. ** please note if you have cdrom. then it may do all that for you
If it's not changed from before, there should be one sticker or some stickers on the outside of your new router. You should find your password printed on a sticker
ON your device in internet settings