How to install Evision(elixir) opencv for vs code

I went through this installation and did the first two steps
which are : $ mix new my_app
and : Then you can add evision as dependency in your mix.exs.

      def deps do
        [
          {:evision, "~> 0.1.9"}
        ]
      end 

so after doing this i got this :


: also Added this thing in mix.exs

and after this i am not able to understand to process of installation