ATC-Lisa,
Firstly, there are computers available at the learning academy, but you're behind the ASA firewall, so some sites you won't be able to access. I have never tried, but I assume things like facebook, etc are blocked, so if you are looking to visit those sort of sites, you will need your own internet elsewhere. Checking of webmail and so forth is allowed however.
As for pay, we got paid on the first pay fortnight after we started, and it was for one week pretty much, given the date we started. So I guess unless there is some drama with paperwork, you should get paid no more than a fortnight after you start. For information, today is pay day if you wanted to work forward to when you start
Also, they should tell you all this, but if you are driving down to Melbourne, you can fill out a form when you get there to get money back for travel expenses. For me at least, it worked out way more than it cost me to get down there, so that's a win
Dress code - in the paperwork they send you, they say corporate wear. Which is what everyone wears..... for about the first week or two until you realise everyone wears whatever they want pretty much. Wear something smart for the first week, then after that as long as the clothes are neat and reasonable, they don't make an issue about it. These days they even give you a couple of Airservices shirts to wear if you want
Good luck with everything, and don't hesitate to ask more questions if you have them