A nice introduction to aspects of Ashtanga Yoga Asana practice.
There is just one thing that David Robson says that I disagree with. He says that Asana is difficult, and that it should be difficult. I am not sure I agree. I think it can be gentle and easy, too. Asana being difficult, the way he seems to mean it, seems focused on achievement of a kind that actually I don't support. The implication seems to be that one ought to achieve certain 'goals' that are too attached to the physical 'look' for my understanding. I think Asana can be easy.