If your video is uploaded to youtube, just add this bit of code "?autoplay=1&cc_load_policy=1" in your embed code at the end of your youtube url. So your embed code looks like this.
If the video you uploaded is on Youtube than stweblack13's advice is absolutely right.
If the video is elsewhere you should tell us more about it.
Also please note that autoplay is always disabled on mobile no matter what you do so this will only work on desktop
If the video is elsewhere you should tell us more about it.
Also please note that autoplay is always disabled on mobile no matter what you do so this will only work on desktop