Ah, true. You are right this assumes some familiarity. Definitely a gap.
Check this out: https://www.theerlangelist.com/article/spawn_or_not
Written by one of the very best Elixir mentors. I believe it will dispel most (hopefully all) of your doubts and clear things up.
I'd also suggest skimming this free ebook: https://erlang-in-anger.com