The first chapter of Introducing Elixir encourages you to play around with the interactive iex system. In this étude, keep using iex, but purposely make errors.

Try leaving out parentheses in arithmetic expressions. Try putting numbers next to each other without an operator between them. Try adding "adam" to 12. Make up variable names that you are sure Elixir wouldn’t ever accept.

That way, you’ll get a feel for the sort of error messages Elixir produces and not be as baffled when you get errors that you aren’t expecting.