After tinkering around in IEX and doing the Getting Started Guide, I'd do Dave Thomas's course (https://codestool.coding-gnome.com/courses/elixir-for-progra...) and read Elixir in Action by Sasa Juric. Dave Thomas's course will get you through the basics of the language and the important concepts step by step. Elixir in Action will go further into the concurrency model that makes Elixir unique.
Finally if you want to build a web app I'd go through the Phoenix Guides: https://hexdocs.pm/phoenix/overview.html#content . Those guides will give you a good example of what a real Elixir/Phoenix Web Application looks like using a database with pooling and request concurrency out of the box. The Programming Phoenix book will take that further (https://pragprog.com/book/phoenix14/programming-phoenix-1-4).
If you want more practice writing functions and algorithms I'd recommend Exercism's Elixir track: https://exercism.io/tracks/elixir or Project Euler (https://projecteuler.net).