Hello. My name is ***** ***** I can help you with your problem. I do not understand your question, partly because of a possible typographical error. What do you mean by "nbn"? And why are you trying to change the password ***** your Telstra wireless router?
Please go to Quick Settings on your kindle by swiping down from the top of the screen. Then select WiFi and look for the network name (SSID) of your wifi network. Select that network and enter the password ***** the card that came with your Telstra wireless router (gateway). The SSID should be on there too.