Can someone help me on how to setup the YouTube plugin?? In the plugin section the YouTube plugin shows that its already installed. If so,how to setup videos?? Can anyone help??

Update : I have successfully set up the YouTube plugin..But now I have two problems
1. I couldnt see any thumbnails of YouTube videos
2. When clicked on a video,it opens up YouTube site instead of opening in my site
In the tutorial video, the video plays in the same page and same website..How do I do that..How could I restore the thumbnails?? confused
