I used an LLM tool to give me little exercises to do, then i'd show my work and it would give feedback, and references for more info. Specifically, https://www.phind.com

Edit* Look, it showed me this same Ask HN post as a reference:

https://www.phind.com/search?cache=avz73b8uy17qz70rfoto0x8t

Also, here is an Awesome list concerning Erlang:

https://github.com/drobakowski/awesome-erlang

And Elixir's HexDocs section on ETS:

https://hexdocs.pm/elixir/erlang-term-storage.html