How do I embed a YouTube video in a text box?
Locate the Youtube video you would like to embed in a text box.
Click Embed.
This displays the YouTube video embed code.
In the text box, click Source.
This displays the HTML code for the text box.
Position the cursor.
Position your cursor where you would like the video embedded, then paste the YouTube embed code (CTRL-V for PC or COMMAND-V for MAC).
Click Source again.
This returns the text box display to normal editing mode. The embedded YouTube video will display as a box marked "iframe." When the item using the text box is posted or saved, it displays the embedded YouTube video.