Thanks for your question. You are correct... you can upload your video to YouTube or Vimeo and then enter the video url into the submission form under the "Video Url" field.
Let us know if you have any other questions.
Will our entries be reviewed immediately, because what if they are viewed by others who use the same ideas or a form of plagiarism? How will we guarantee our work or make sure we are judged for our originality or creativity if someone else views our entry and submit items they saw in our video? And considering some might have to resubmit more than once the time stamp wont help much.