'How to add Youtube videos to your CMS Site'
To start, go to the youtube video that you want to add to your site. On the right hand side, is an 'embed' link code. Copy that code (Right click and click copy, or click the copy code button) and return to your CMS site.
Open the page you want the youtube video on, and click the 'Source' button on the content editor. It's the button on the top left of the FCK editor.
Paste the code in here, and click the source button again. You may not see the youtube video in the editor, but a white box. This is perfect! Save the page, and go have a look at it on the webpage.