Update README.md

Author: dragonmantank

README.md

@@ -88,22 +88,26 @@ $opentok = new OpenTok($apiKey, $apiSecret, $options);
 #### Migrating to Vonage Video API
 
 There is some useful behaviour on initialization in this SDK that will help as a stopgap before switching out from the
-legacy TokBok API to the new, Vonage Video API. To do this, you add a `private_key_path` and
-`application_id` into the `$options`. Note that the SDK will read the private key path from the root directory of 
-the SDK, so you will need to adjust the directory structures accordingly.
+legacy TokBok API to the new, Vonage Video API. To do this, you can pass in an Application ID for the API Key, and the path to
+a Vonage private key as the API Secret.
 
 ```php
 use OpenTok\OpenTok;
 use MyCompany\CustomOpenTokClient;
 
-$options = [
-    'application_id' => 'your_application_id',
-    'private_key_path' => './path-to-your.key'
-]
+$applicationID = '61bb2dae-9b69-400c-9abb-642d082af5fc';
+$privateKey = './private.key';
 
-$opentok = new OpenTok($apiKey, $apiSecret, $options);
+$opentok = new OpenTok($applicationID, $privateKey);
 ```
 
+The SDK will notice that the authentiction has changed, and will automatically start to forward requests to the Vonage API Routes
+instead of the OpenTok API Routes. All requests and responses in your code should be exactly the same as they are on the
+OpenTok API.
+
+**NOTE:** The SDK will read the private key path from the root directory of your project (generally one level above the docroot
+of your application), so you will need to make sure that the path provided is either absolute, or relative to your project root.
+
 ### Creating Sessions
 
 To create an OpenTok Session, use the `createSession($options)` method of the