Most international airlines allow passengers to carry only 20 kg of luggage so you will not be able to bring all of your belongings with you! Deciding what you need here can be a very hard decision.
Adelaide has good shopping facilities and so you will be able to buy clothes, stationery, cooking equipment, electrical goods (such as smart phones, electronic tablets, alarm clocks, calculators etc) in Australia. However, electrical goods can be expensive here and may be cheaper if purchased duty-free or bought in your home country. If that is what you are planning to do, the standard voltage in Australia is 240 volts. Electric plugs normally have three flat pins as shown. However, adaptors can be found in some electrical stores and cost about A$10 to buy.
A small number of typical souvenirs from your home country will make excellent gifts for homestay families and new Australian friends. Also, traditional or national dress from your home country may be useful for cultural, religious and other special occasions.
Most Australians, especially young people and students, dress casually. While you may need some good, smart clothes for special occasions, in general you should bring mainly casual clothes in which you feel comfortable. Jeans, T-shirts, shirts, jumpers, shorts, light dresses and skirts are all common. In winter you may want to bring a waterproof jacket or a warm coat.