That is an embeded code, so you only use the part in bold for the youtube video. So, if you look for a part of the embedded code to your youtube video, use it in between the two tags it should work.
I hope it helps, I tried to explain it my best.
I hope you don't do all of that yourself; unless you're good at easily spotting out the video ID in the midst of all of that. ): If you look at the embedded coding and the bold set of information you pointed it, you'll notice it's part of the actual video's URL. Basically all you have to do is follow what donvannj stated.
In the URL, C&P the last tidbit "V=___________" and put that in the middle of the Youtube tags.