Pick a car. Get in it. Drive for 24 hours.
What exactly is it you need to know? What car to use? Look in the write-ups section - at least two of us have written up all A-spec 24 hour endurance races.
Oh, and that website can't be all THAT great, seeing as it's not actually open yet. Please refrain from advertising other websites here. And, in case you're interested, Sony have recently started suing for using the GT logo on a website...