The simplest way to insert a video to HTML is to embed a YouTube player to your page. The YouTube widget that is a part of N1ED is exactly for that.
With this add-on you can find a video on YouTube (search by keywords or specify the exact URL) without even leaving the editor, configure how it should display and embed it to the page. At any moment in the future, you can adjust parameters of the video: start/end time, autoplay, subtitles, etc.
A video can be embedded just like in the classic CKEditor (insert between paragraphs or use text flow), or in the Bootstrap 4 support mode - you can insert a video into a cell (column) in the structure, and the video becomes responsive providing correct displaying of it on different devices (with different screen width).