For complete beginners of Ashtanga Vinyasa Yoga, I recommend a brief exchange by telephone prior to your first visit.
In my own experience, individual classes are the best way to be introduced into Ashtanga Vinyasa Yoga. In addition, or alternatively, regular participation in the Mysore-style classes is advised. I offer a 4-weeks-trial phase at reduced prices.
If possible, you should bring your own yoga mat (for the first couple of classes, I can lend you a mat), a towel and clothes to change into after class, as one usually sweats quite heavily.
Please note that it is not advisable to eat within 3 hours and to drink within 30 minutes of the class.