1) Install two Node.js modules babel and babel-cli one after another. Note: if you have some troubles during installation, update your Node.js and NPM to the latest stable versions.
npm install --global babel
npm install --global babel-cli
2) Install a set of plugins for available ES6 (ES2015) features. Without these plugins you will get errors about unexpected token or similar. See http://babeljs.io/docs/plugins/preset-es2015/ for more details about supported ES6 features.
npm install --global babel-preset-es2015
3a) Start interactive REPL and type ES6 code. Note: globally installed modules on Windows are located under C:\Users\<Username>\AppData\Roaming\npm\node_modules
> let arr = [1,2,3]
> arr.map(x => x * x)
Output: [1,4,9]
Output: [1,4,9]