Astanga yoga consits of six series of yoga. All with the same sun salutation, opening series, and closing sequence. Just the middle portion of the series changes. There is a Drishti in each posture where you focus you attention and eyes to a certain location. This adds focus to the mind and difficulty to the system.
Since this yoga is not for beginers it is neccasary that you start with the primary series. Many people even like to do half primary while begining or taking an easy day. This consists of stoping at navasana then moving on to the closing sequence. Here I just show primary series because to go beyond one really needs a teacher.