I misspelled one of the tags when I was showing you how to do it, but I fixed it now.
If you like, I can edit your posts for you so that the videos are embedded.
To embed a youtube video into the forum, put the jumble of letters and numbers of the url, which for your let's play is YLqr35KZm7Q, inside the [youtube] tags, so that you get [youtube]YLqr35KZm7Q[/youtube]