Update README.md

Author: ltrudu

README.md

@@ -6,7 +6,11 @@ Android 10 limited access to device identifiers for all apps running on the plat
 
 **Zebra mobile computers running Android 10 are able to access both the serial number and IMEI** however applications need to be **explicitly granted the ability** to do so and use a proprietary API.
 
-To access the serial number and IMEI file on Zebra Android devices running Android 10 or higher, first declare a new permission in your AndroidManifest.xml
+To access to this API, you must first register your application using the AccessMgr MX's CSP.
+You can do it using StageNow, more details here: https://github.com/darryncampbell/EMDK-DeviceIdentifiers-Sample
+Or you can use this wrapper that will automatically register your application if it is necessary.
+
+To use this helper on Zebra Android devices running Android 10 or higher, first declare a new permission in your AndroidManifest.xml
 
 ```xml
 <uses-permission android:name="com.zebra.provider.READ"/>
@@ -54,6 +58,10 @@ dependencies {
 }
 ```
 
+Add the module DeviceIdentifierWrapper as a dependency to your application.
+
+Now you can use the following snippet codes to retrieve IMEI number and Serial Number information.
+
 Snippet code to use to retrieve the Serial Number of the device:
 
 ```java
@@ -105,3 +113,34 @@ Snippet code to use to retrieve the Serial Number of the device:
         });
     }
 ```
+
+As the previous methods are asynchronous, if you need both information, it is strongly recommended to call the second request inside the onSuccess or onError of the first request. 
+
+Sample code if you need to get both device identifiers:
+```java
+     private void getSerialNumber()
+     {
+         DIHelper.getSerialNumber(this, new IDIResultCallbacks() {
+             @Override
+             public void onSuccess(String message) {
+                 // The message contains the serial number
+                 String mySerialNumber = message;
+                 getIMEINumber();
+             }
+
+             @Override
+             public void onError(String message) {
+                // An error occured
+                // Do something here with the error message
+                // Then call the getIMEINumber method
+                getIMEINumber();
+             }
+
+             @Override
+             public void onDebugStatus(String message) {
+                // You can use this method to get verbose information
+                // about what's happening behing the curtain             
+             }
+         });
+     }
+```