J4 Developer Resources
Boilerplates
Boilerplates are skeleton extensions designed for you to modify to begin building your own extensions.
Example 1 - A Component Boilerplate
https://github.com/ceford/j4xdemos-com-bpsrcDownload and unpack this in your project file space, not in your test web-site tree. After download, make all the changes indicated in the README and you are ready to go.
Example 2: A Boilerplate for Component, Module and Plugin
https://github.com/joomla-extensions/boilerplateAgain, download and make all of the changes in the README.