add new aws steps

Author: mongoKart

source/fundamentals/authentication.txt

@@ -153,12 +153,23 @@ MONGODB-AWS
    The ``MONGODB-AWS`` authentication mechanism is available only for
    MongoDB deployments on MongoDB Atlas.
 
-The ``MONGODB-AWS`` authentication mechanism uses your Amazon Web Services
-Identity and Access Management (AWS IAM) credentials to authenticate your
-user. You can either specify your credentials explicitly
-or instruct the driver to retrieve them automatically from an external source.
+The ``MONGODB-AWS`` authentication mechanism uses a user's Amazon Web Services
+Identity and Access Management (AWS IAM) credentials to authenticate them to MongoDB.
 
-The following sections contain code examples that use the following placeholders:
+To use AWS authentication, first perform the following steps:
+
+- Add the ``MongoDB.Driver.Authentication.AWS`` NuGet package to your project.
+- Add the following line of code to your application's bootstrap code to register the
+  AWS authentication provider:
+
+  .. code-block:: csharp
+
+     MongoAuthentication.RegisterAwsAuthenticationProvider();
+
+After you register the AWS authentication provider, you can either specify the AWS IAM 
+credentials explicitly or instruct the driver to retrieve them automatically from an
+external source. The following sections describe both of these methods. 
+The code examples in these sections use the following placeholders:
 
 - ``<awsKeyId>`` - value of the AWS access key ID
 - ``<awsSecretKey>`` - value of the AWS secret access key

source/upgrade/v3.txt

@@ -144,3 +144,8 @@ Version 3.0 Breaking Changes
 
 - The ``MongoClient`` constructor accepts only one ``Credential`` object instead of an
   array.
+
+- To use Amazon Web Services (AWS) authentication, you must add the
+  ``MongoDB.Driver.Authentication.AWS`` package to your project and register the
+  authentication provider in your application's bootstrap code. To learn more about
+  using AWS authentication with the {+driver-short+}, see :ref:`csharp-mongodb-aws`.