I gave a talk about this a few weeks ago. It covers a lot of Elixir’s concurrency and OTP, from the basis to relatively complex hierarchies and ideas.

A Winner is you: A practical introduction to concurrency in Elixir

I suggest searching for talks by Torben Hoffmann. His talks are heavy on the business argument of choosing Erlang (and Elixir), and how to do stuff with OTP.

• Erlang Patterns Matching Business Needs: Erlang Patterns Matching Business Needs by Torben Hoffman
• Thinking like an Erlanger: Thinking like an Erlanger - Torben Hoffmann
• Explore Elixir using board game logic: Explore Elixir using board game logic - Torben Hoffmann

If you only watch one I suggest the Exploring Elixir using board game logic.

Also the ElixirConf talks by Saša Jurić are all brilliant.

I haven’t seen any yet, but I’m reading through a new book called Designing for Scalability with Erlang/OTP. I know that’s not exactly what you were asking for, but the book focuses exclusively on OTP frameworks. There’s one chapter early in the book that acts as a “refresher” for Erlang, which is really all you’ll need if you’re familiar with Elixir, so don’t let the Erlang title scare you away.