you will need to set the IP address of your machine in the same range as the router.

If the routers IP address is for example 192.168.0.1 make your PC 192.168.0.2

Same as if its 10.0.0.1 make your pc 10.0.0.2

Then try connecting to the router using http://192.168.0.1 or http://10.0.0.1 or whatever it might be.

Your instructions should tell you the default address it uses.