updated the guide doc.

docs/guide/bootstrap.md

 Bootstrap with Yii
 ==================
 
-A ready-to-use Web application is distributed together with Yii. You may find
-its source code under the `app` folder after you expand the Yii release file.
-If you have installed Yii under a Web-accessible folder, you should be able to
-access this application through the following URL:
+Yii provides a few read-to-use application templates. Based on your needs, you may
+choose one of them to bootstrap your project.
+
+In following, we describe how to get started with the "Yii 2 Basic Application Template".
+
+
+### Install via Composer
+
+If you do not have [Composer](http://getcomposer.org/), you may download it from
+[http://getcomposer.org/](http://getcomposer.org/) or run the following command on Linux/Unix/MacOS:
+
+~~~
+curl -s http://getcomposer.org/installer | php
+~~~
+
+You can then install the Bootstrap Application using the following command:
 
 ~~~
-http://localhost/yii/apps/bootstrap/index.php
+php composer.phar create-project --stability=dev yiisoft/yii2-app-basic yii-basic
 ~~~
 
+Now you should be able to access the Bootstrap Application using the URL `http://localhost/yii-basic/www/`,
+assuming `yii-basic` is directly under the document root of your Web server.
+
 
 As you can see, the application has four pages: the homepage, the about page,
 the contact page and the login page. The contact page displays a contact
@@ -20,29 +35,17 @@ and the login page allows users to be authenticated before accessing privileged
 The following diagram shows the directory structure of this application.
 
 ~~~
-app/
-   index.php                 Web application entry script file
-   index-test.php            entry script file for the functional tests
-   assets/                   containing published resource files
-   css/                      containing CSS files
-   img/                      containing image files
-   themes/                   containing application themes
-   protected/                containing protected application files
+yii-basic/
    yii                    yii command line script for Unix/Linux
    yii.bat                yii command line script for Windows
+   requirements.php       the requirement checker script
    commands/              containing customized yii console commands
-      components/            containing reusable user components
    config/                containing configuration files
       console.php         the console application configuration
       main.php            the Web application configuration
    controllers/           containing controller class files
       SiteController.php  the default controller class
-      data/                  containing the sample database
-         schema.mysql.sql    the DB schema for the sample MySQL database
-         schema.sqlite.sql   the DB schema for the sample SQLite database
-         bootstrap.db        the sample SQLite database file
    vendor/                containing third-party extensions and libraries
-      messages/              containing translated messages
    models/                containing model class files
       User.php            the User model
       LoginForm.php       the form model for 'login' action
@@ -56,6 +59,10 @@ app/
          contact.php      the view for the 'contact' action
          index.php        the view for the 'index' action
          login.php        the view for the 'login' action
+   www/                   containing Web-accessible resources
+     index.php            Web application entry script file
+     assets/              containing published resource files
+     css/                 containing CSS files
 ~~~