I need help bridging Netgear (C6250)

I have a my existing Netgear modem/router (C6250) so I can connect my new Orbi satellite.I don't have a password that I know of for the router. I'm not a technical wiz, but looks like I need to connect my computer by ethernet to the modem/router. I have done that and am trying to follow the directions to  put "routerlogin.net" into browser. did that and the netgear website comes up, not a menu that includes advanced tab > Advanced set up. 

Can anyone help me.