How do I program the repeater without connecting to router?

I just bought a wireless range extender, it is a Hawkins HWREG1, I receive an internet signal in my apartment that is unsecured, but I can only connect in one spot. The store said I would not need to connect to the router or modem, but it is requiring an IP address and during set up does not recognize the connection. I know the IP address for access changes, can any one help with what I need to do to configure this repeater to detect that and the roaming IP's?