This manual explains how you can adjust the settings of a video in the front-end editor. Note: this article does not cover the videos added with the text editor.
Because YouTube videos start playing when you click on it, you can not select the element that by clicking on it. Instead, you can look up the element in the parts list that you find in the blue upper bar.
Once you have selected the element you can adjust the properties with the top button in the left bar.
In the url you place the url of the youtube video you want to play.
If "Show open link" is checked, a link will be shown below the video with which the visitor can open the video in YouTube itself.
With the "Hide related videos" checkbox you can prevent suggestions from being shown on similar videos at the end of video playback.