NPM : You must have to npm install packages. You can do this by running npm install from the root of your project to install all the necessary dependencies :

$ npm install

Run npm run dev for a dev server. Navigate to [http:https://localhost:3000] . The app will automatically reload if you change any of the source files.

$ npm run dev 

$ npm run generate

$ npm run build
$ npm run start

For detailed explanation on how things work, check out Nuxt.js docs.