For the YouTube embed codes on ATRL, you have to take the code that's after the "watch?v=" part, so that'd be: https://www.youtube.com/watch?v=PNu_-deVemE
There's 3 sizes you can do~ YTMUSIC: Smallest one, mainly just used so people can listen to the song.
How to do~ [yt.music]PNu_-deVemE[/yt.music] (WITHOUT THE DOTS)
YTMINI: Medium-sized, used for watching the video but not taking up as much space.
How to do~ [yt.mini]PNu_-deVemE[/yt.mini] (WITHOUT THE DOTS)
YOUTUBE: Biggest size, used to watch the video and take up a larger amount of space.
How to do~ [you.tube]PNu_-deVemE[/you.tube] (WITHOUT THE DOTS)