Well, you need to go into your CMD. Type CMD or Command Prompt into your search bar (start) and click on it and run it. Now, type in 'ipconfig' without the quotes. A bunch of information will come up. You need to find your IPV4 address and type that into your browser. IE; 192.168.0.1 is mine. Type that address into your browser.
Your router/modem page will come up, but depending if you have a login (user/pass) you may have to login to access it. Once you get into it, you're gonna wanna find a page that says something like Port Forwarding, or something. That's as far as I can help you because I don't have your router. Try looking it up on Google - I'm sure you'll get some results.