There is a better way to find out your own router's address, without going to that website. We give advice here not just links to other advice which may not be good enough. It isn't addictive and is perfectly safe to follow the advice below.
Press your Windows key and R together then in the Run box, type
and hit the Enter key.
A lot of enties will appear and the one you need is Default Gateway. Take the reference from that and put it into your browser's URL bar as if it were an Internet address.
The next barrier will be the password to go any further and sometimes admin as the login name and admin for the password. It should be printed somewhere in the case of the router.