This document provides instructions for integrating AngularJS into an existing legacy HTML application. It describes how to add an Angular "micro-app" by specifying a container div with Angular directives like ng-app and ng-controller. The Angular code, including a module, controller, and function calls from the legacy code, can be kept separate. Template views can also be added using ng-view and routing configuration. The process is described as relatively simple and allowing incremental integration of Angular without rewriting the entire application.