Lara Schenck recorded a Sloppy Screencast (what a cool name!) of her talk at the Hollywood WordPress Meetup in LA.
She broke it up in Part I and Part II and also published here notes on Gist.
First, she explains what a Gutenberg Block is and then she walks us through Ahmad Awais 's Create-Guten-Block tool.
Here are Lara's Notes as a Gist on Github
We used Daniel Bachhuber's Gist Gutenberg Block to embed it.