If you watched the video and didn't fall asleep (it's kind of boring, sorry) then you can probably answer this simple question in the diagram below.
Also, if you weren't too bored by the video, then congratulations: You must really love chess! That means that you'll improve quickly.
It is White to play. White should play: a) Bxg7+! planning to play the powerful Qh6+ next. This leads to checkmate or the win of material. b) h4! with the intention of playing Bg5#. Black will not have a good defense after h4! c) Too easy. Qg6#
Hint: You don't actually HAVE to watch the whole video, you can just "fast forward" to 2:23