diff --git a/examples/public/client_credentials.php b/examples/public/client_credentials.php
index c1ca45f0..e2547df3 100644
--- a/examples/public/client_credentials.php
+++ b/examples/public/client_credentials.php
@@ -1,8 +1,14 @@
 <?php
+/**
+ * @author      Alex Bilbie <hello@alexbilbie.com>
+ * @copyright   Copyright (c) Alex Bilbie
+ * @license     http://mit-license.org/
+ *
+ * @link        https://github.com/thephpleague/oauth2-server
+ */
 
+use League\OAuth2\Server\AuthorizationServer;
 use League\OAuth2\Server\Exception\OAuthServerException;
-use League\OAuth2\Server\Grant\ClientCredentialsGrant;
-use League\OAuth2\Server\Server;
 use OAuth2ServerExamples\Repositories\AccessTokenRepository;
 use OAuth2ServerExamples\Repositories\ClientRepository;
 use OAuth2ServerExamples\Repositories\ScopeRepository;
@@ -14,31 +20,33 @@ use Zend\Diactoros\Stream;
 include __DIR__ . '/../vendor/autoload.php';
 
 $app = new App([
-    'settings'    => [
+    'settings'                 => [
         'displayErrorDetails' => true,
     ],
-    Server::class => function () {
+    AuthorizationServer::class => function () {
         // Init our repositories
-        $clientRepository = new ClientRepository();
-        $accessTokenRepository = new AccessTokenRepository();
-        $scopeRepository = new ScopeRepository();
+        $clientRepository = new ClientRepository(); // instance of ClientRepositoryInterface
+        $scopeRepository = new ScopeRepository(); // instance of ScopeRepositoryInterface
+        $accessTokenRepository = new AccessTokenRepository(); // instance of AccessTokenRepositoryInterface
 
-        $privateKeyPath = 'file://' . __DIR__ . '/../private.key';
-        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';
+        // Path to public and private keys
+        $privateKey = 'file://path/to/private.key';
+        //$privateKey = new CryptKey('file://path/to/private.key', 'passphrase'); // if private key has a pass phrase
+        $publicKey = 'file://path/to/public.key';
 
         // Setup the authorization server
-        $server = new Server(
+        $server = new AuthorizationServer(
             $clientRepository,
             $accessTokenRepository,
             $scopeRepository,
-            $privateKeyPath,
-            $publicKeyPath
+            $privateKey,
+            $publicKey
         );
 
-        // Enable the client credentials grant on the server with a token TTL of 1 hour
+        // Enable the client credentials grant on the server
         $server->enableGrantType(
-            new ClientCredentialsGrant(),
-            new \DateInterval('PT1H')
+            new \League\OAuth2\Server\Grant\ClientCredentialsGrant(),
+            new \DateInterval('PT1H') // access tokens will expire after 1 hour
         );
 
         return $server;
@@ -46,18 +54,28 @@ $app = new App([
 ]);
 
 $app->post('/access_token', function (ServerRequestInterface $request, ResponseInterface $response) use ($app) {
-    /* @var \League\OAuth2\Server\Server $server */
-    $server = $app->getContainer()->get(Server::class);
+
+    /* @var \League\OAuth2\Server\AuthorizationServer $server */
+    $server = $app->getContainer()->get(AuthorizationServer::class);
 
     try {
+
+        // Try to respond to the request
         return $server->respondToAccessTokenRequest($request, $response);
+
     } catch (OAuthServerException $exception) {
+
+        // All instances of OAuthServerException can be formatted into a HTTP response
         return $exception->generateHttpResponse($response);
+
     } catch (\Exception $exception) {
+
+        // Unknown exception
         $body = new Stream('php://temp', 'r+');
         $body->write($exception->getMessage());
 
         return $response->withStatus(500)->withBody($body);
+
     }
 });