AngularJS routing in codepen

https://codepen.io/a_shokn/pen/yEJpww?editors=1010

var myApp = angular.module('myApp', ['ngRoute']);

myApp.config(function ($routeProvider) {

    $routeProvider

    .when('/', {
        templateUrl: 'main.html'

    })

    .when('/second',{
         templateUrl:'second.html'

    })

});

Here is the Link to my Code Snippet , My Question is Were Must we keep our files (in my case main.html and second.html) when using routing in anjular js

Source: AngularJS