Question: how to download a video from youtube to keynote?
Answer: Open your presentation in Keynote.
Open Safari and get the Video URL. Open the video in your web browser – go to Youtube, open the video and right click and select 'Copy URL'
Run LiveSlides. Launch 'LiveSlides' and paste the URL (Apple – V' )into Liveslides. Liveslides will put the link for the live video into Keynote.