Setup ArangoDB your favorite way so thats listening at least on 127.0.0.1:8529.
Go to the web ui and add a collection tweets.
ArangoDB is ready and we install the demo:
git clone https://github.com/baslr/arangochair-serversendevents-demo
cd arangochair-serversendevents-demo
npm install
node index.js
Now the demo is running and we can try it out: open multiple tabs in your browser with the address 127.0.0.1:3000 and tweet something.