The Angular 2 "Tour of Heroes" app is the example app found here on the angular website.
First, download the project's node modules by running the following command in the root directory of the project. Note that the root directory of the project has a package.json file which lists all of the required modules.
npm install
This command will download the node modules specified in package.json and install them in a directory called node_modules. When the install command completes, run the following....
npm start
This command will start a local development server on port 3000. You can now view the app by navigating in a browser to localhost:3000.