As a video?
Luckily for you, I researched that whole thing like a month ago for Super Junior's SFS teaser...(Thank you google!)
Go to the share button.
To the right of the link, there's two buttons, embed and email. Click the embed button.
There will be a code underneath, and that's the code you copy and paste.
Honestly, this should be put in the FAQ, I don't know why it isn't >.<

So do you mean like putting that YT vid on your ff or something? If yes then comment on my wall or something. If this is not what you're looking for then sorry, I can't help.