Hi Billie_Jean09,
You're welcome! It's very easy. When you have a specific youtube video in front of you, at youtube.com, you can either click on "enclose" ( not sure of the english phrase, as I only see the Dutch word.) You will see something lighting up blue in a box. It starts with <object. Copy that entire thing and paste it in a post using the post reply instead quick reply. The alternative is is to single-click on the video and click on the copy embed video and then you paste it in your post.
A third method ( without the sizing in the lower right corner) is to take the url at the top and remove everything except the code ( Vrty76&bn890 i.e.) and then you use the BB code ( not sure if they have to be higher case for the Y and the T) One of these should work. Let me know if you get the hang of it.
Good luck!