Purpose and character would be why you made the video using their content.
Amount would be how much of the copyrighted content you used. (In your case, 10 seconds out of a 15 second video, about 66%)
Effect of use and value would most likely be what is gained from using their content in such a way that it qualifies as your own.
I'm not entirely sure what nature would be referring to.
Your best bet would be to take this to support at:
www.support.tm . They can help you better than other users can.