Don't stress about learning to cue like a madman.....no-one's expecting you to be an expert straight away! Just listen to your instructor and how they cue things (couple of beats in advance), the type of words they use and how they vary the level/tone of their voice.
Also, listen to the music and try to get a feel for how the moves change with the music and how moves layer on one another.
Try to get to as many classes as you can before your training (without going overboard though - you don't want to be exhausted for the training!). Maybe ask your instructor to keep an eye on your technique to see if there's anything you can tidy up quickly - but don't stress, your trainer will really work on any problems.
Then there's the usual - take plenty of snacks and drinks as you don't get all that many breaks to eat so make the most of them! Also, take a few changes of clothes as it's not nice sitting in cold, sweaty gym gear while you're doing theory sessions......
Finally, enjoy it ok - it's be one of the best experiences of your life.