Install the gatsby CLI:
npm install -g gatsby-cli
For detailed instructions, see here.
Install dependencies:
npm install
Start the dev server:
gatsby develop
Even if you have Node 14.5 you might get an error:
Gatsby requires Node.js 14.15.0 or higher (you have v14.5.0)
Install the latest node and you should be good to go.
You should now be able to view the site at http://localhost:8000/.
This project is based off the gatsby default starter, so for now, that's a good place to go for information