Check what there is to see and do in Australia. You have to visit at least two citiess and the Coral Reef. Plan at least one activity per day. Do not forget to include things in the mroning, afternoon, evening and night. Make sure it is appealing to most students. Be ready to explain why you chose those activities: cost? educational value? Recreation? Keep track of admission costs.
Organiser: Write down the information of each place. Remember this is an itinerary for students your age so you should speak to them.
Economist: Keep track of fees and timetable. Remember to allow time to rest and have a bite.
Designer: Compile everything on the dossier. Look for pictures to illustrate the planning. You can use padlet, canva, mural.ly or any other web 2.0 tool of your choice.