To use this feature please make sure you have installed all required plugins. This post Require Advanced Custom Fields plugins that available after you installing add on.
You can add your favorite video from youtube or vimeo with paste the video url or you can embed the code, you also can upload your own video to your site.
Please note:If you desires to use embed or url from youtube, you should paste the Share URL instead of video url (at address bar). You can find share URL button below video box on youtube (with share icon).