And you found it while we were building a tutorial, excellent! The one caveat is that if the YouTube link has the word "embedded" or "youtu.be" in it, the link will not work. In that case, go back to your video and look for the "Share" button underneath the video. Click on that and it will show you a short link. You don't want that, as that will be the "youtu.be" version, instead click the tab that says "long link", highlight, and copy that. Alternatively, highlight and copy the title of the video, and search for it in YouTube again. It should be the first video that comes up, open that, and the link at the top in the browser window will be the long version again. If it still doesn't work, shoot the tech team an email or PM us, and we'll do our best to fix it for ya. (Sometimes, we'll see them on our own and fix them anyway, but we don't always catch everything)
Where to find the other link on YouTube that will work:
An extra option is that you can choose where in the video you'd like it to start playing from. Say you have a TED talk that's an hour and a half, but you want everyone to listen to the points made at minute 55:30. Click the button next to the blue arrow and enter the start time!