Navigate to the video on YouTube.
Copy the title of the video, the name of the person who created the video -- a username can be used as a last resort -- and the URL of the video.
Arrange your information according to the format your teacher has requested.
APA: Name of Creator. Video Title [Video file]. Retrieved from [URL]. (Note that [Video file] should be included with the brackets.)
Chicago: Name of Creator. Video Title. Online video. Accessed [access date]. [URL].
MLA: Name of Creator. "Video Title." YouTube. Date of access.