At the tech art roundtable day 2 at GDC there were questions about USD, so here are some links to the artist resources mentioned:
Book of USD: Book of USD - Getting Started with Universal Scene Description (USD)
USD in 15 minutes: https://youtu.be/JixC53cQn5U
Would love to see any others that are more artist friendly, as usually all the resources on USD are only programmer/engineer friendly.