Download the example or clone the repo:

curl https://codeload.github.com/zeit/next.js/tar.gz/master | tar -xz --strip=2 next.js-master/examples/with-react-helmet
cd with-react-helmet

Install it and run:

npm install
npm run dev

Or alternatively:

yarn
yarn run dev

Deploy it to the cloud with now (download)

now

This an minimalistic example of how to combine next.js and react-helmet. The title of the page shall be changed to "Hello next.js!" The rest is all up to you.