Okay, this sounds like a problem getting setup with the build tools:
– Make sure you’re working with the plugin inside your /wp-content/plugins folder
– You will want to run
npm install in the main folder with the package.json file in it
– If you want to edit the files, the best thing to do is run
npm run dev first (npm run build is more meant for when you are done and want to run the build one final time)
If you have errors from running any of these commands, please post them up and we’ll get you up and running.