just a rough place of where to start
install a fresh version of WordPress
follow this tutorial
Notice the registerBlockType function on the block.js file.
Then make another block, yet name it something different than ‘hello-world’. Switch out some of the functioning to get an idea how it works.
Next, check out some of Zac Gordon’s videos out:
An Overview of registerBlockType for Building Blocks with Gutenberg in WordPress
more at Gutenberg Handbook
Check out Matt’s AWP Gutenberg collection