Just show up and don't worry. They'll instruct you in everything you need to know and it's time consuming going over the same stuff with everyone who phones to book a session - especially when it's all got to be repeated anyway at track time.
There is nothing specific that you need to know before the class other than relax, don't take it too seriously and have fun.
Yes take your pedals along and use a rental. Save the fancy Serotta for if you decide that the track is for you.