As stated in subject.
Just like any other youtube video … just find and install any youtube downloader app for your browser.
For what it’s worth I recommend this one (which I personally use):
The tool I use is youtube-dl.
For Mac, I use Downie available here…
It costs but works with lot’s of sites.
Thanks for all the replies, it would be useful to have some of them off line.
This one is great, and free, thanks!
This one works well too.