1. Hover your mouse over the blue play button at the bottom lefthand corner of the screen.
2. Click on the red button that appears ("Preview Wideo").
3. Click the "close" button or anywhere outside of the preview pop up to return to the editor.
In the preview wideo pop up you will see these buttons:
A. Play video
B. Stop video
C. Mute video
D. Adjust volume
E. Current time/video length
H. Close preview