Here is a useful site for the basics of Elixir:

https://elixirschool.com/en/

In particular at the moment I am interested in Plugs:

https://elixirschool.com/en/lessons/specifics/plug/

There is a gotcha that caught be out: you need to visit http://127.0.0.1:8080 rather than http://localhost:8080

The next trick will be to deploy a trivial web application to heroku.

More on plugs: https://github.com/chriseyre2000/plug_demo

Once I am happy with Cowboy then I can move on to Phoenix.

Here is the plug sample: https://github.com/chriseyre2000/plug_demo

This is a trivial website application. It allows an http interface to be put onto an Elixir/OTP application. That is where things get powerful.