Added a flow diagram (and a whole overview section)

Author: memildin

articles/security-center/built-in-vulnerability-assessment.md

@@ -24,6 +24,23 @@ This feature is currently in preview.
 > [!NOTE]
 > Security Center supports the integration of tools from other vendors, but you'll need to handle the licensing costs, deployment, and configuration. For more information, see [Deploying a partner vulnerability scanning solution](partner-vulnerability-assessment.md). You can also use those instructions to integrate your organization's own Qualys license, if you choose not to use the built-in vulnerability scanner included with Azure Security Center.
 
+
+## Overview of the integrated vulnerability scanner
+
+The vulnerability scanner extension works as follows:
+
+1. Azure Security Center deploys the Qualys extension to the selected virtual machine/s.
+
+1. The extension conducts the vulnerability assessment and reports back to the Qualys cloud service in the defined region.
+
+1. Qualys's cloud service then sends the findings to Azure Security Center.
+
+1. The findings are available to you in Security Center.
+
+[![Process flow diagram for Azure Security Center's built-in vulnerability scanner](media/built-in-vulnerability-assessment/va-vm-flow-diagram.png)](media/built-in-vulnerability-assessment/va-vm-flow-diagram.png#lightbox)
+
+
+
 ## Deploying the Qualys built-in vulnerability scanner (Standard tier only)
 
 The simplest way to scan your Azure-based virtual machines for vulnerabilities is to use the built-in vulnerability scanner. 
@@ -72,7 +89,7 @@ To see the findings and remediate the identified vulnerability:
 
     [![List of findings from Qualys for all selected subscriptions](media/built-in-vulnerability-assessment/va-findings-all.png)](media/built-in-vulnerability-assessment/va-findings-all.png#lightbox)
 
-1. To filter the findings by a specific VM, open the "Affected resources" section and click the VM that interests you. Alternatively, select a VM from the resource health view, and view all relevant recommendations for that resource.
+1. To filter the findings by a specific VM, open the "Affected resources" section and click the VM that interests you. Or you can select a VM from the resource health view, and view all relevant recommendations for that resource.
 
     Security Center shows the findings for that VM, ordered by severity. 
 
@@ -161,7 +178,7 @@ When you open the recommendation, you'll see your VMs in one or more of the foll
 The scanner is running on your virtual machine and looking for vulnerabilities of the VM itself. From the virtual machine, it can't scan your network.
 
 ### Does the scanner integrate with my existing Qualys console?
-The Security Center extension is a separate tool from your existing Qualys scanner and, because of licensing restrictions, must be used within Azure Security Center.
+The Security Center extension is a separate tool from your existing Qualys scanner. Licensing restrictions mean that it can only be used within Azure Security Center.
 
 ### Microsoft Defender Advanced Threat Protection also includes Threat & Vulnerability Management (TVM). How is the Security Center Vulnerability Assessment extension different?
 Microsoft is actively developing world-class vulnerability management with Microsoft Defender ATP's Threat & Vulnerability Management solution, built into Windows.