1. Open the video on youtube.

2. Click "Share" then click "Embed"

3. Select "Enable privacy-enhanced mode"

4. Copy the embedded code, paste in notepad, and edit the two links in it.
   There must be two youtube links!

The two links will look like this for example 
src="http://www.youtube-nocookie.com/v/6n2Y---r67A?fs=1&hl=en_US"

The links start and stop with the quotation marks ""

5. Type
   &autoplay=1 before the last quotation mark for both links.

The above link will now look like this for the two links
src="http://www.youtube-nocookie.com/v/6n2Y---r67A?fs=1&hl=en_US&autoplay=1"

6. Copy the entire code and paste it in your html editor.
   It will now work.




P.s. To test it out though, after you put in the &autoplay=1 in the two links
     of the embed code in notepad save the notepad as video.html and save. Open
     video.html and it should autoplay. If it does then you know that your edited
     embeded code is CORRECT.