In general, I found starting with a Erlang/Elixir framework tutorial helps. Phoenix includes a generic wrapper on top of PostgreSQL (Ecto provides data mapping and language integrated query), and hit a surprising number of users per host with trivial code (common game engine back-end.)

https://www.phoenixframework.org/

https://www.amazon.com/Programming-Phoenix-Productive-Reliab...

If you don't run away from a framework intro, then dive into the details of the OTP:

https://www.amazon.com/Designing-Elixir-Systems-OTP-Self-hea...

https://www.amazon.com/Elixir-Action-Third-Sa%C5%A1a-Juric/d...

The only foot-gun I would initially avoid, is a fussy fault-tolerant multi-host cluster deployment. Check out RabbitMQ package maintainers, as those guys certainly offer a fantastic resource for students ( https://www.rabbitmq.com/docs/which-erlang .)

Best of luck =3