I recommend to explore the official documentation first as Siddarthan Sarumathi Pandian told. After that, you might want to give a try to Portainer.io. It's an administration UI for Docker designed to simplify Docker usage.

Disclaimer: I work for Portainer.io

The official documentation is the best. Try running the hello world docker example. Once you do that, you can try setting up a node js app on docket - here's a sample app, github.com/spsiddarthan/nodejs-hello-world

Talking of layers, once you build an image of your own, try analyzing it using this link: imagelayers.io

That should set you right.

Update: I am up and running with this :D My first app will be out by this weekend. Thanks, Siddarthan.