You should beable to use the router and a seperate modem on the same BB line.
To setup router
1. connect router to master socket.
2. connect router to laptop with an ethernet cable
3. setup router with username password and check you can connect to your ISP/internet.
4. set up the wireless in the routerand laptop, remove cable and check you connect by wireless.
5. refit cable an set security for the wirelss connection.
6 remove cable and check wireless connection again.