pubspec.yaml. This file almost always contains a dependencies section, where you will install the Angel3 framework libraries.angel3_static, angel3_cache, angel3_jael, and angel3_cors.pub get on the command line, or in your IDE if it has Dart support. This will install the framework and all of its dependencies.bin/main.dart. Put this code in it:var app = Angel() - The base Angel3 server is a simple class, and we need an instance of it to run our server. The name app is a convention adopted from Express. In general, call an Angel3 instance app. This has no effect on functionality, but it makes it easier for other developers to understand your code.app.get("/", (req, res) => "Hello, world!"); - This is a route, and tells our server to respond to all GET requests at our server root with "Hello, world!". The response will automatically be encoded as JSON. Head over to the Basic Routing tutorial to learn about routes, and how they work.await http.startServer(...) - This asynchronous call is what actually starts the server listening. Without it, your application won't be accessible over HTTP (as it won't ever listen for requests).