Hover your mouse over the video to reveal the controls. Select share from the upper left.
The embed code will be one of the options.
The <iframe> embed code can then be inserted into any of the Gutensite modules that have a text editor. Just be sure to switch to “code view” before pasting, otherwise, the system will only display the code, not actually use it.
Also, check the “Allow raw HTML” box, if available.