Hi SONE0413, welcome to ATARNotes and thanks for posting your question on here

To start, i've moved your thread to VTAC Discussion, given your question is primarily about uni course applications.
Secondly, you will find a list of dates for the VTAC course preference/release process here:
http://vtac.edu.au/dates.htmlApplications for uni courses opens on 1 Aug 2016 at 9am, and close on the 29th September at 5pm. You can submit a list of preferences (courses you want to be considered for) during this period. This is all done online using the VTAC system, so there's that!
Your friend is correct - you can basically go overseas as soon as you complete all of your exams. Just make sure you have internet access whilst you're overseas, and make sure you check your email / VTAC account every so often.
Some dates that i'll highlight for you:12 December 7am - You get your ATAR! (via SMS if you register or online using resultsandatar).
20 December noon - VTAC (course preference)
change of preference closes - this means you basically have 8 days from when you get your ATAR to rearrange your preferences, add some, delete some and so on (you might do this for a variety of reasons - e.g. unexpected ATAR, personal preference)
18 January 2017 2pm - your Round 1 uni offers come out via your VTAC account and sent to your email.
Just a few other things to think about:
- You may need to attend an enrolment session when you get your uni offer (some unis like to do this). You can nominate someone else to go if you have a relative in Australia when you're overseas.
- The uni semester starts around the last week of February or the first week of March. Ideally I reckon you should be back around mid February at the latest.
All the best.