First things first.
Connect your computer to the router with a cable.
Open a CMD prompt and type IPCONFIG then hit enter
It will give you your IP address and the IP address of the router as the gateway. Be sure your computer is set to receive DHCP addresses and that you dont have an assigned one. If you are using DHCP and have a 192.168.x.x address then you should be fine with accessing the router.
Open a web browser and type in the
http://<gateway address from above> and then hit enter. That address should start with the same 3 octets as your IP address so it should be 192.168.Y.X. Y should be the same as yours from above and X can be either 1 or 254.
If you are getting a 169.x.x.x address then you are either not connected, not getting DHCP and need to figure out why. Could be a bad cable, bad port, bad router or a miss configured client.