Editor

You may want to import in your blog the video from another blog account on youtube, myspace... For instance
if your video is very heavy
if you do not have the video file available on your computer

Select the video from youtube that you want to import: click on the video to launch it

Get the embed code for THE VIDEO
copy the code <object width="480" height="295"><param name="movie" value="http://www.youtube.com/v/GSuJq4UzkIA&hl=fr&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/GSuJq4UzkIA&hl=fr&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="295"></embed></object>

this is what you will need to paste inside your blog entry

Click on create Content

Select Blog entry (not video, that choice is meant for uploading a file which is located on your computer)

Set the "body field" to disable rich text (below field area)

Copy the embed code from the video inside the body field, do not edit

And click on Submit and your video is available