Assume a handstand position, with your feet supported by a wall. Begin with your scapula elevated, PPT (tuck your tailbone), squeeze your glutes, legs together & brace your core.
Maintain total body tension, and start bending your elbows, your head and shoulders should move forwards in front of your hands. Build up range so you can touch your forehead to the floor.
Grip with your fingers, glutes & core tight, drive through the floor and push yourself back up. Arms fully extended at the top, scapula elevated. Repeat for repetitions.
Avoid letting your elbows drift backward or flare out, keep them stacked above your hands. Maintain your hollow position as your push up, maintain ppt, don't allow your lower back to extend.