After you arrive in Australia, the first thing you must do is to find a place to stay. You may have organized rooms already through your friends and families in Australia. If you have no family and friends, then you may find short term accommodation through your college or university. You need to visit your provider and see how far it is from the place you live.
You need to make sure that you enrol at the right date so please read carefully your offer letter and COE.
You have to open bank account, obtain Tax File Number and buy Mobile.
Please check link below for more detailed planning on arrival in Australia: