The somehow lenghty keynote (3h), that introduces the background ideas leading up to the language, and the language itself,
"A Future of Value Semantics and Generic Programming"
https://www.youtube.com/watch?v=4Ri8bly-dJs
https://www.youtube.com/watch?v=GsxYnEAZoNI&
If you want to skip it and go straight to the source, it is located at,
https://github.com/val-lang/val