This guide refers to a Rosewill RNX-EasyN4 router, but will apply to most Rosewill routers in general.
1. Access the router's browser-based utility.
Log into your router’s browser-based utility by entering 192.168.0.1 or your default configuration IP into a browser. The default username and password are both admin.
5. Enter OpenDNS resolvers.
Enter 208.67.222.222, 208.67.220.220 respectively in the "First DNS Server" and "Secon DNS Server" fields.