This is how you post a YouTube video:
1)Click the "Reply" button to start your post and write anything you like about the vid you're going to post.
2) When ready to place the video in your post, you will need opening and closing tags for your video. Type these tags for enclosing your video:
(I am using a jpg picture of what you should type above because I can't literally type this without it becoming code in my post)
3) So you will now see those "youtube" tags in a desired place in your post, now go to the YouTube page with your video. Look in the address bar at the top. You are looking for the web address. It should look something like this, which is the address for the video below.
or like this
4) Copy and paste the YouTube video number between the tags that you typed as in picture above. In the example above (and below), the YouTube video number is at the end or in-between "v=" and "&feature=related". I shall highlight it in red below.
5) Your final result will look like this (again I'm using a picture, as literally typing this will put the video in my post instead of showing you how to do it.
6) Now finish your post, click Submit Reply (or "Preview Post" to make sure the video is there) and you've embedded a YouTube video (The one below uses "HUmFUVrQMkM"