Both the video and the Gatsby blog post show you how to get started in using Gatsby with React. It definitely helps if you have done some React.js programming because then the utilities required like Node, npm, yarn , and Webpack will not only be around but familiar to use.
What Gatsby Reveals About React.js
Note the frustration of a newby to React as illustrated by some of the underlying React code in Gatsby:
1)easier development of derived components
2)easier to understand the code layout components
4)broader set of interfaces to other systems with GraphQL, Node.js, REST API, etc.
Finally, React is accumulating a broad set of endorsements not the least of which is its use in Gutenberg and Calypso for the major ongoing upgrade of WordPress. Considering that WordPress is used on 24% of all the websites in the world this is an impressive endorsement beyond the fact that React is the primary Web language of Facebook, Reacts inventors.