Start in downward facing dog, lower your arms, hover your chest over the ground to the front, come into upward facing dog. Try to go the same way backward. If possible, keep your knees above the ground when going back. Going back is the hard stuff.
Exercises
Butterfly with Thera Band
Bring your resistance band under tension behind your shoulders. Arms are stretched to the sides. Bring your straight arms together in front of your chest.