adding prereqs in

-------
cc: @batamig

Author: batamig

articles/defender-for-iot/organizations/tutorial-getting-started-eiot-sensor.md

@@ -111,6 +111,8 @@ You can also download, and add the [Azure public IP ranges](https://www.microsof
 
 A sensor is needed to discover, and continuously monitor Enterprise IoT devices. The sensor will use the Enterprise IoT network, and endpoint sensors to gain comprehensive visibility.
 
+**Prerequisites**: Make sure that you've completed [Set up a server or Virtual Machine (VM)](set-up-a-server-or-virtual-machine-vm) and [Prepare your environment](#prepare-your-environment), including verifying that you have the listed required resources.
+
 **To set up an Enterprise IoT sensor**:
 
 1. Navigate to the [Azure portal](https://portal.azure.com#home).
@@ -242,4 +244,4 @@ For more information, see:
 - [Manage your IoT devices with the device inventory for organizations](how-to-manage-device-inventory-for-organizations.md)
 - [View and manage alerts on the Defender for IoT portal](how-to-manage-cloud-alerts.md)
 - [Use Azure Monitor workbooks in Microsoft Defender for IoT (Public preview)](workbooks.md)
-- [OT threat monitoring in enterprise SOCs](concept-sentinel-integration.md)
+- [OT threat monitoring in enterprise SOCs](concept-sentinel-integration.md)