In order to access your Optimum router settings, you will need to enter the IP address of your router into a web browser. The default IP address for Optimum routers is 192.168.0.1. Once you have entered this IP address into your web browser's URL bar, you should see a login page for your router appear.
On this login page, you will need to enter the username and password for your router in order to gain access to the settings page. The default username and password for Optimum routers is usually admin (without the quotes). Once you have logged in, you should be able to change any of the settings on your router as desired.