It’s super easy. For Vimeo, just put your video number inside of [vimeo] tags like this:
[xxx]8118698[/xxx] (replacing xxx with vimeo)
[vimeo]8118698[/vimeo]
and for YouTube the same thing, but using the youtube video letters like so:
[xxx]emP5D9Klssg[/xxx] (replacing xxx with youtube)