Welcome here at GT planet! You can learn a lot from the people here so make sure to ask your questions here, Especially people like Famine (and many others) have pretty much all the answers you are looking for and are happy to answer all questions you might have.
It reallly helped me to improve my driving when I joined, and wish I had done that sooner as it would have made my progress in the game so much easier.
first of all to answer your question: you can qualify on softs and then change tyres after qualifying if you prefer to do so (and if the race rules for a particular race allow, meaning that there is more then one tyre compound available for that race). the qualifying session does not count for the mandatory tyre rule.
I have a few tips for you that will help you discover most you need to know about the GT FIA races:
- most importantly: check Mistah his guides on youtube before every FIA race; These are fantastic and will show you how to drive a lap at the track, which tyre/pitstop strategy is needed and lots more.
- practice in free practice using a ghost car from a top 10 driver. Also practice entering the pit so that you know where it is. (why? I could not find the pits once in a race at Tokyo and ran out of fuel
)
- join races in the lobby to practice with tyre wear and dealing with other drivers, etc
- sent friend requests to fellow drivers, you can compare laptimes and see their laps in replay (my PSN is mcl1974 if you want to sent one to me)
- do not let dirty drivers and idiots discourage you, some races can be very frustrating but the many awesome races you will have are worth it
- race clean yourself, do not drive others of track or pull dirty moves as that might be retaliated. Do not be that guy!!!
hope this will help a bit. good luck!!!