This plugin is far from feature-complete.
If you want to improve it, feel free to pick one of the open issues and give it a shot.
In case you need any help, just add a comment to the issue to get a conversation started. 😃
Open this repo in VSCode, and you should be able to just Start the launch task "Launch Extension":
You might need to wait a moment for the first npm install to finish. You can see progress in the "running build tasks" section of VSCode:
Run make package to package a .vsix file.
To get a list of all available commands, try make help.
To test your changes, go to the Debug panel in VSCode and click on the play button. This will start the extension in a new window where you can test it.