There is a PDF file of the User Manual at - click here
<<< I find that the web address for the setup is unavailable >>>
If you mean that by entering the router's IP address (192.168.1.1) into a web browser, you are not managing to access it, try giving the PC's network adapter a fixed IP address in the same range - 192.168.1.2 with subnet mask 255.255.255.0
Presumably you are using a "wired" connection to the router for the initial configuration? This is normally necessary until the wireless settings have been configured.