Ashtanga Yoga led “modified Primary Series ( which means that each student practices a sequence of postures at his own pace, instructed by the teacher.

Yogakurse für Anfänger | Ashtanga Yoga Heidelberg

Ashtanga Yoga Beginners Guide

There is no reason to worry if you never did it before. Everything will be explained and all the postures, one by one,  will be introduced to you by the teacher.