[Click on the picture with the
right button of your mouse, then on ‘picture-in-picture’
in the menu and
finally place your cursor on the picture at the bottom of the
screen to display the ‘Play’
icon [i.e. the white arrow pointing towards the right] to start
the clip, which will thus play in ‘picture-in-picture’
mode.
[Please note that I have left the
English of these non-native speakers as is.]