Read Rex Grigg's guide at www.rexgrigg.com
. It's full of the information you need. Then, come back here and read, read, read. These forums are even MORE full of info, but Rex's guide puts it more simply.
To answer a couple of your questions... No undergravel filter or heater is needed and could actually prove to be a pita later (plant roots growing into it, if it goes out you'd have to uproot all the plants to fix it, etc.). Also, the factory light on your tank is most likely not good enough ~ you need something with a 6500 kelvin rating or higher. And don't use the usual aquarium gravel ~ you'll need something finer, I think in the range of 2mm particle size. I use Soilmaster Select, but I don't know if you can get that in Australia.
I'm still fairly a newbie, but am having a blast because I've started slowly. I took my own advice and read Rex's site and these forums, then got my feet wet with a ten gallon low tech tank. I've got easy to grow plants in it (hygros, hydrocotyle and pellia) and it's stuck in a window, no lights except dappled sunlight, no filters and no CO2. No fish either ~ just a bunch of algae eating shrimp. The link is in my signature if you want to take a look. It was so easy
Since that tank, I've just recently "graduated" to ones with lights ~ I bought some compact spiral bulbs and have 30 watts over my ten gallon tank, DIY CO2 soon to be added. Now I'm learning by experience about that, relying heavily on what I've read. THAT is what makes it easier, knowing the basics from reading, so I have some sort of map to go by instead of just a shot in the dark.
One of these days I'll graduate even higher, to pressurized CO2 and bigger tanks, but for now I'm content to play around with my ten gallon tanks. I have five of them, three of them set up and planted. I like having multiples since if one of the tanks goes south, I can keep my chin up by looking at the ones that are doing good.
Good luck! You're going to have SO much fun!