First, navigate to the YouTube Video you want to embed on your site.
Click Embed (you can also simply copy the Share link and copy the url into the Video content on your webpage. Embedding gives you some more options though, including eliminating the suggested videos screen when the video ends.
Click Show More
Deselect Show suggested videos... to prevent YouTube from suggesting videos after the current video is complete. (Content can sometimes exceed PG rating.)
Copy the html code.
Navigate to your Streamline sandbox and click Edit this content on the page you want to embed the video
Select HTML and past the HTML code in this box
Click Save and close
Your video is embedded on your site! That's it. You're done.