With a population of approximately 2 million people, Brisbane is the capital of Queensland and the third-most populous city in Australia. It is well and widely known as a diverse and laid back travel destination, and there are tons of Brisbane hostels to choose from.
The main area for hostels in Brisbane is Upper Roma Street, which is also a good spot for meeting other backpackers. If you arrive to the transit station (via bus or train), just go out and head right on Roma Street until it changes to Upper Roma Street, and you're there. The locals are very friendly, so don't hesitate to ask for directions if needed.
Brisbane is divided into many districts, which each hold their appeal for different types of people. Some of them worth mentioning are of course the CBD (shopping and tourist sites), South Bank (with the artificial "lagoon"), and Fortitude Valley (the nightlife district, which is also considered one of the best live music scenes in all of Australia).
Brisbane is well equipped for a backpacker and the hostel prices are reasonable. There are also a few bars and restaurants catering especially for backpackers, you'll find good meal deals in these places.
Your best option of transport inside the CBD is just plain walking, or bicycle if you have one or get one for a good price (your hostel may have information on bike rentals). Even the inner suburbs can be reached pretty quickly by bike. But if you're heading out of the city, it's better to choose one of the public transport options. TransLink operates the ferries, buses, and trains which form the public transport system in Brisbane, it's recommended to check their website for further details or ask at your Brisbane hostel. There is also a rickshaw service available, called "Green Cab".