You can create a simple "hello world" application using Interplay.

Start with an Http node (get) request, name the URL click on done and click deploy.

Also add a Http Response node along with a NodeJS Function node. Connect all nodes.

Click on the NodeJS Function node add msg.payload = "Hello World" click on done and click on deploy.

To test if the Hello world application worked go on the browser and type 

https://(Instance Name).interplay.iterate.ai/(Get request name)