Hiya @bean! Sorry about that - I’ve edited the post for you now.
Correct me if I’m wrong, but had you added them as links using the hyperlink button in the editing window?
Either way, all you need to do is copy and paste the url e.g youtube.com/blahblah directly into the editing window on a new line (with no extra text either side of it) and then hit enter, and you should see the video load in the preview video on the right. Here’s a screen grab to show what I mean:
Hope this helps!