The whole thing about STD/STIs, it is basically what you were taught in school, just do a simple google search to help refresh your memory.
Basically brothels are legal in NSW because they licensed, so sex workers must practice safe sex, so only sex with a condom.
You can also get blowjobs with a condom or a bareback one, but that depends on how cautious you are (stats are very rare and very low, like I said "how cautious"). Let the girl know if you prefer a blowjob with or without condom.
Personally I don't worry about this, the girls know what they are doing and will be practicing safe sex.
What to expect is a complicated one depending on where you are intending to visit and what girl you end up with.
If you are visiting Ginza (good place for a first time), then make a booking, go by xboyx suggestions for girls or any other reviews on this forum, match that with their roster -
http://www.ginzaclub.com.au/Roster
Ginza is basically your high end ultimate experience type place (if you are losing your virginity, why not), Ginza has lots of reviews for lots of different girls, with positive experiences.
If you are visiting 42G or another place (you let us know where you intend to visit), then probably do a line up. This is where the available girls not currently with someone do a quick line up say their name and you have to remember your favorite.
Every guy has different tastes, so my recommendation for girl may not suit your tastes, this is why I like line ups, I can live with my own mistakes!
If you are not interested in any girl during a lineup, don't worry and don't feel pressured to just take any girl (this was a mistake I made at my first visit), just drive or visit another place, you could be visiting at a very busy time.
If visiting a tiered shop (basically something that has basic, premium and diamond service) for a first experience just pay for diamond, until you know what you like. You don't have to use all the options available, just lets you relax not think too much about it.
Besides tiered shops, other places are the all inclusive (called full service sometimes), barring extras for CIM, talk to the shop directly as they are the best at explaining that to you.
Tell shops it is your first time there, they should be more than happy to help explain things, they want your money at the end of the day, so make them earn it! Who know you may become a regular there and they will never need to explain anything to you again.
At all venues, the girls' photos may not always look exactly like them, I assume you understand how photoshop works. The same happens everywhere else as well, my tinder dates did not look like their photos either. People will always try to put their best face forward.
What to expect when there sex depends on the girl, the girls all have their routines, let the girl lead you, if you don't like something, let the girl know.
Also let the girl know that it is your first time, so they maybe are able to help you out during the session.
You also shower before and after sex at every venue (I personally shower at home first, so a basic quick one there).
Most girls don't have a good grasp of English (I have assumed you are likely visiting an Asian place and not Stiletto, Liaisons, etc...), if you speak their language, then great, if not just use simple English with basic terms, they all should understand the basic sex terms.
Oh and if you look under 18, make sure you bring ID, the venue may refuse entry for obvious reasons.
Here is a little humour for you, I actually brought condoms to my first visit, never used them as the girl had her ones handy on the bed while mine were in my pants further away.
Don't have extremely high expectations of your first time, it might not be all cracked up to be in your imagination, you may cum too soon, or whatever, so just relax and have fun. You will get better with experience as you learn how your body works.
I had an girlfriend (who I now hate, lol) where we taught each other a lot about sex, my first time was an absolute dud.
Here is a great guide for acronyms, I was pretty lost on this forum without it -
http://forum.aus99.com/showthread.ph...-Abbreviations
Happy punting and treat the girls well!