1.Place the two mounting straps over your headrest with the mount's sponge facing headrest, and release button on top.
2.Adjust to your deserved viewing angle, then firmly secure the mount by tightening the straps.
See diagrams below.
FITTING PORTABLE DVD PLAYER TO HEADREST MOUNT 
Gentle slide the Portable DVD player down by aligning the backpanel groove with the headrest mount, until you hear the click sound.
See diagram below.