You need to pass an absolute path with a link to the video file. By using only the video.mp4 you’re telling the browser to look for the file in the same directory as your html file; since your using Codepen, that won’t work unless you use Codepen assets.
And controls ="movie.mp4 is not the attribute you’re looking for. Read this.
Ah, OK. You just need to point to a video file through the Internet. For example, this link: https://www.sample-videos.com/video/mp4/720/big_buck_bunny_720p_1mb.mp4