Embedding vids on this site is really easy from YouTube.
The third symbol from the right in the reply box looks like a little strip of film. You have your YouTube, (or other) vid up, click on the shore option and a link box will appear below it. Right click on that link box with your curser over it and click copy. Then here, click on the film symbol, a box will appear for your link, right click and then fleft click paste. Then post the reply.