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. To close the player window, click anywhere outside the pop-up.
In the preview wideo pop up you will see these buttons:
A. Play video
B. Stop video
C. Mute video
D. Adjust volume
E. Playhead
F. Current time/video length