Im at where it says "app/controllers/controllername_controller.rb" and i dont get what files its talking about
There are four sections of the Rails kit for Codecademy, shown here.
On the left is the instructions.
The top middle is the file editor.
The bottom middle is the console.
The right is the browser.
We are concerned with the file editor. In the top left corner of that editor is an icon of a file. Click it! It will take you into the file directory, where you will navigate first to 'app', then 'controllers', then click 'controllername_controller.rb'. You will then open the file, and input whatever they want you to do.