After downloading the DFY videos from the members area, upload them to your YouTube channel. Then copy just a part of the code of the video. You can copy it from the link you see after your video is successfully uploaded to your YouTube channel.
Or you can copy it from your browser tab or from within your embed code.
Next, open your index html using notepad++. Scroll down and look for the YouTube code. Replace part of that code with the one you copied from your youtube video.
If you want your video to autoplay when someone visits your site just add this code ?rel=0&autoplay=1 after your YouTube URL.