ok go to your facebook. On the right hand side in the box marked applications you should see the video icon. Click on that.  That will open you up to a screen that will show you the videos you have already uploaded as well as people in your network.  At the top right hand corner (above the video clips) it will say upload.  Then it will take you to the screen where it says Create a new video and browse.  So select the video from your  pc.  Click on the file and the rest is pretty much self explanitory