Justin, you lucky man!
It's hard to get tickets for company class and, of course, it always takes place in the working day so it means time off work to go. I have been once, and adored it.
Get there about a quarter of an hour ahead of the time on your ticket, to be at the front of the line of people waiting to be taken up to the studio. The seating is bleacher seating (fixed benches). You enter the studio from the right, so go straight over to the left side and sit in the front row near the door. That's where the dancers come in and you can wave to those you know, or those you wish you knew - they are very friendly and usually return a greeting. The piano will probably be over to the right.
The ballet master/mistress will ask you all to be quiet as mice and switch off your mobiles, but you may applaud at the end of class. Class begins with exercises at the bar, then moves into the centre with more and more action as the class progresses - this gets very exciting. I think class usually ends with adage, and lasts about ninety minutes to two hours. You probably don't know whether you are seeing boys in class, girls in class, or mixed class. When company class first opened to spectators you could choose, but so many people wanted to see the boys that the box office has stopped announcing which class it would be!
It's fascinating to listen to the ballet master/mistress's instructions, and the pianist is quite amazing. In fact, the accompanist is the unsung hero of most ballet classes, probably playing about sixty numbers in the course of class, and all joined quite seamlessly.
Enjoy - and do please post a message afterwards.