No. You can start learning elixir and you'll learn about how the BEAM works on the way. You'll also eventually learn about Erlang/OTP libraries and probably that's when you'll start reading basic erlang code but that should come (mostly) naturally. I included some tips in another comment here.
Ah thanks.
A very good place for elixir questions is https://elixirforum.com/ community is super friendly and you will often get questions answered by core team members or even Robert Virding (one of the Erlang creators).