In all descriptions of the taijiquan form the front of the form routine is when I am facing you. The left and right facing forms are when I am facing to the left and right, and the back facing form is when I am looking away from you. The back facing postures have pictures showing the posture from the front, or head on view.
For consistency, I describe the postures from the feet-up. That is, I describe the footwork of the posture first, followed by the movement of the arms and hands. Sometimes the footwork description is repeated to illustrate the coordination of the feet and hands.
You are already familiar with the footwork of the Sun Style Taijiquan form; it is the Five Phases Stepping exercise. There is not, however, a direct correlation between the Eight Trigram Circling exercise and the torso movements of the Taijiquan form. But, not to worry, for most of the postures, the hands move in unison and describe arcs with the movement of the torso.
Throughout the form, the width of the steps should be natural for your ability. Use the stepping pattern and the Open Hands/Close Hands postures to synchronize your movements with your breath.