To do the exercises, just edit the files with your favourite editor.
If you want a live-edit experience, install BrowserSync.
To install BrowserSync:
npm install browser-sync@2.7.1
To run the live-edit web server:
browser-sync start --server --port 4000 --files index.html --files css/main.css
It should open the url http://localhost:4000 immediately. Editing index.html or css/main.css would cause the browser to automatically refresh.