Go to YouTube and find the video you want

1. under that video click on the word share

 2. on the left under where it says share click on embed .

3. a box comes up with video on the left and code is on  the right.

4. copy that code so you can paste to your page.

5.after you paste see this in front     again only change the word ony iframe to embed

7.  Go back to code . under the size  see where the code begins with http

look through that code till you see a ?

8. after that ?  add         &autoplay=1&       

9.

make sure you didn't make spaces      . save ,go look it's on your page as auto play