You can think of Mix as your Elixir Utility Belt. It builds your projects, runs tasks for you, runs your tests, installs packages - a fascinating tool. That comes later - right now open up your terminal and navigate to a directory where you can save your work.

This is one of many projects you'll be creating so make a redfour directory on your drive somewhere.

mix new physics

You should see some stuff splash on your screen:

* creating README.md* creating .gitignore* creating mix.exs* creating config* creating config/config.exs* creating lib* creating lib/physics.ex* creating test* creating test/test_helper.exs* creating test/physics_test.exsYour Mix project was created successfully.You can use "mix" to compile it, test it, and more:    cd physics    mix testRun "mix help" for more commands.

As you can see Mix created the skeleton of an application for you. There are different ways to think about this structure - as a package that's part of a library or as an app in its own right. Right now don't worry about it we'll get to that later.