Update README.md

Added additional options for existing Azure vNet and Subnet

Author: ajkeane-aws

README.md

@@ -10,22 +10,42 @@ To begin the deployment process, ensure that you have the necessary prerequisite
 
 Before running the deployment script, please ensure that you have the following parameters readily available:
 
+#### The following parameters are mandatory
+
+- *Deployment Type (`-d`):* Choose whether you want to use a `new_vnet` or an `existing_vnet`.
 - *Location (`-l`):* The Azure region where you want to deploy your resources, such as `eastus`.
 - *Resource Group (`-r`):* The name of the Azure Resource Group where the deployed resources will be managed, e.g., `aws-datasync-rg`.
 - *Virtual Machine Name (`-v`):* The desired name for the Azure Virtual Machine that will host the AWS DataSync Agent, for example, `datasync-vm`.
 
+#### The following parameters are mandatory when the value of `-d` is `existing_vnet`
+
+- *VNET Resource Group (`-g`):* The name of the Azure Resource Group with the existing VNET, e.g., `existing-vnet-rg`
+- *VNET Name (`-n`):* The name of the existing VNET, e.g., `existing-vnet`
+- *Subnet Name (`-s`):* The name of the subnet that exists in the VNET, e.g., `existing-subnet`
+
 ---
 
 This script has been developed to run on an Amazon Linux 2 AMI and the EC2 instance should have at least 160GB of disk space for the conversion process
 
 ![Amazon EC2 Launch Instance](./docs/datasync.png)
 
+### Download the Deployment Script
+
+Run the following command to download the deployment script from the code repository.
+
+`curl -sLO https://raw.githubusercontent.com/aws-samples/aws-datasync-deploy-agent-azure/main/src/bash/datasync.sh`
+
 ### Running the Deployment Script
 
 Once you have your parameters ready, you can initiate the deployment script using the following command:
 
-sudo bash datasync.sh -l eastus -r aws-datasync-rg -v datasync-vm
+If you would like to deploy the DataSync VM in a new VNET: 
+
+`sudo bash datasync.sh -d new_vnet -l eastus -r aws-datasync-rg -v datasync-vm`
+
+If you would like to deploy the DataSync VM in an existing VNET:
 
+`sudo bash datasync.sh -d existing_vnet -l eastus -r aws-datasync-rg -v datasync-vm -g existing-vnet-rg -n existing-vnet -s existing-subnet`
 
 ## Deployment Steps
 
@@ -53,7 +73,7 @@ The deployment script automates several steps to ensure a smooth integration bet
    The script will facilitate the seamless upload of the converted HVD file as a managed disk within the specified Resource Group. This disk will contain the AWS DataSync Agent.
 
 8. *Create Virtual Machine:*
-   Leveraging the uploaded managed disk, the script will assist you in creating an Azure Virtual Machine. This Virtual Machine will host the AWS DataSync Agent and enable data synchronization between AWS and Azure.
+   Leveraging the uploaded managed disk, the script will assist you in creating an Azure Virtual Machine in either a new VNET or an existing VNET. This Virtual Machine will host the AWS DataSync Agent and enable data synchronization between AWS and Azure.
 
 ## Clean Up
 
@@ -62,7 +82,6 @@ Once the deployment script has successfully executed and the AWS DataSync Agent
 - *Delete Amazon Linux EC2 Instance:*
   The Amazon Linux EC2 instance that was used for the deployment can be safely deleted. The script will have completed its tasks, and the instance is no longer required for the ongoing operation of the integration.
 
-
 Thank you for using the *AWS DataSync Deployment for Azure* repository. We hope this tool proves valuable in streamlining your data synchronization between AWS and Azure environments.
 
 ## Security
@@ -72,4 +91,3 @@ See [CONTRIBUTING](CONTRIBUTING.md#security-issue-notifications) for more inform
 ## License
 
 This library is licensed under the MIT-0 License. See the LICENSE file.
-