just login to your router. it is most likely 192.168.1.1 user:admin default password: password or admin or (nothing) Or it may say on the bottom of your router. then just go into wireless and security
you cant, thats why he is saying you have to log in and see what it is, or if your router doesnt tell you, change it, and this time dont forget to wire it on a sticky note and put it on your router