Here's how to post any Youtube video, so the video appears within your post.
First, you need to upload your video to Youtube. These instructions don't cover that part. (We don't support uploading and storing videos within the WhitneyZone software. They take up so much disk space, it would cost much more to host the web site.)
On the Youtube page where you can view your video, just below the video window, click the "Share" button. That opens up a space showing you the link that brings people to that Youtube page. Next, click the "Embed" button (you are "embedding" the video into this forum.) An area opens below the button showing the code starting with the <iframe...
You can simply copy that code and paste it into your post, but I prefer to do a little more. Below the box with the code to copy are some boxes: (small, medium, large, etc, and "Custom", showing some numbers representing width and height dimensions.) Our board runs best with pictures at width=800. So plug in "800" in the Custom Width spot, and it will set the height automatically, AND will change the code to copy.
Now, copy that code (the <iframe... stuff) and paste it into your post.
Below the forum's posting window, make sure to set the Markup to "using HTML and UBBCode", and it is ready to submit.