Add XML excerpt and screenshots to documentation

README.md

@@ -1,2 +1,85 @@
 # Packer.Images [![Build Status](https://ci.spamasaurus.com/api/badges/djpbessems/Packer.Images/status.svg?ref=refs/heads/Server2019)](https://ci.spamasaurus.com/djpbessems/Packer.Images)
 
+This OVA appliance allows deploying a Windows Server fully automated; either as a domain member or stand-alone server.  
+
+The included `.ovf` file has the following XML contents (simplified for clarity) to facilitate the different `DeploymentOption`s:  
+```xml
+<Envelope [...]>
+  [...]
+  <DeploymentOptionSection>
+    <Info>Deployment Type</Info>
+    <Configuration ovf:id="domainmember">
+      <Label>Domain member</Label>
+      <Description>Windows Server joined to an Active Directory domain</Description>
+    </Configuration>
+    <Configuration ovf:id="standalone">
+      <Label>Stand-alone</Label>
+      <Description>Stand-alone Windows Server</Description>
+    </Configuration>
+  </DeploymentOptionSection>
+  <VirtualSystem ovf:id="[...]">
+    [...]
+    <ProductSection>
+      [...]
+      <Category>1) Operating System</Category>
+      <Property ovf:configuration="domainmember standalone" ovf:key="guestinfo.hostname" [...]>
+        <Label>Hostname*</Label>
+      </Property>
+      <Property ovf:configuration="standalone" ovf:key="guestinfo.administratorpw" [...]>
+        <Label>Local administrator password*</Label>
+      </Property>
+      [...]
+      <Category>3) Active Directory membership</Category>
+      <Property ovf:configuration="domainmember" ovf:key="addsconfig.domainname" [...]>
+        <Label>Domain name*</Label>
+      </Property>
+      <Property ovf:configuration="domainmember" ovf:key="addsconfig.username" [...]>
+        <Label>Domain account username*</Label>
+      </Property>
+      <Property ovf:configuration="domainmember" ovf:key="addsconfig.password" [...]>
+        <Label>Domain account password*</Label>
+      </Property>
+    </ProductSection>
+  </VirtualSystem>
+</Envelope>
+```
+
+When **provisioning** the appliance through the vCenter 'Deploy OVF template...' wizard, or through vApp-compatible *Infrastructure as code* tooling (e.g. HashiCorp Terraform), it is possible to provide all relevant configuration through vApp properties.  
+
+<table>
+<tr>
+<td><em>vSphere 'Deploy OVF template...' wizard</em></td> <td> <a href="https://registry.terraform.io/providers/hashicorp/vsphere/latest/docs/resources/virtual_machine#deploying-vm-from-an-ovfova-template">HashiCorp Terraform vSphere provider</a> </td>
+</tr>
+<tr>
+<td><img src=".assets/vAppConfigurations-Server2019-example.png" alt="vApp properties" width="400" /><br/><img src=".assets/vAppProperties-Server2019-example.png" alt="vApp properties" width="400" /></td>
+<td>
+
+```hcl
+  vapp {
+    properties = {
+      # "deployment.type"           = "domainmember"
+
+      "guestinfo.hostname"        = "TF-SRV01"
+      # "guestinfo.administratorpw" = var.vm_adminpassword
+      # "guestinfo.ntpserver"       = "0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org"
+      "guestinfo.ipaddress"       = "10.0.0.42"
+      "guestinfo.prefixlength"    = "24"
+      "guestinfo.dnsserver"       = "10.0.0.21"
+      "guestinfo.gateway"         = "10.0.0.1"
+
+      "addsconfig.domainname"     = "contoso.com"
+      "addsconfig.username"       = "CONTOSO\\Administrator"
+      "addsconfig.password"       = var.adds_password
+    }
+  }
+```
+
+</td>
+</tr>
+</table>
+
+On first boot, the appliance will start **configuring** itself without any further user-input, by performing the following steps:  
+- Change hostname
+- Configure network
+- Join Active Directory domain **-OR-** Set password for local administrator
+- Iterate through any payload scripts