Lemme guess, default router as supplied by telstra? XD I have the exact same router at home so I'll get you a list of steps when I get home
The technicolors default to 10.0.0.138 for the router address, and they have extra crappy admin interfaces so I don't blame you for the trouble you're having took me a while to find out how to do something as simple as changing the default ip settings!
Better publish it out on the interwebs somewhere, since it seems like when searching for this router model #...a lot of people are wondering how to port forward lol.