Well, it easy actually...here's the baby-step:-
as you can see, below is the screenshot of youtube.com as you're watching certain videos...
Did you notice the box just at the right side of the video?
If you do, just click on the embed code like in the picture below. The following option of player will popup just right under the box. Now you can choose your preferred video size and scheme color.
Alternatively, you can just directly copy the embed code into your blog post to choose the default video skin. But you have to make sure that you are viewing the post table in html format like in the picture below.
(If you noticed, there're two option in viewing the post edit format; Compose and Edit Html)
To ensure that your video code is working, just press the 'Preview' button at the top-right of the post table. You'll have the video player in your post table as viewed below.
Muzamir, i hope there's trouble-free with my tutorial and easy for you to work it out!