Issue #130 - Updated README.md from review comments

Author: rakillen

samples/docker-domain/README.md

@@ -1,18 +1,24 @@
-Example Image with a  WLS Domain
-================================
-This Dockerfile extends the Oracle WebLogic image by creating a sample WLS 12.2.1.3 domain and cluster from a WebLogic Deploy Tool model.
+Example Image with a WLS Domain
+===============================
+This Dockerfile extends the Oracle WebLogic image by creating a sample WLS 12.2.1.3 domain and cluster. Utility scripts are copied into the image, enabling users to plug Node Manager automatically into the Administration Server running on another container.
 
-Utility scripts are copied into the image, enabling users to plug Node Manager automatically into the Administration Server running on another container.
+The Dockerfile uses the createDomain script from the Oracle WebLogic Deploy Tooling (WDT) to create the domain from a text-based model file. More information about WDT is available in the README file for the WDT project in GitHub: 
 
-### WebLogic Deploy Tool
+https://github.com/oracle/weblogic-deploy-tooling
 
-The WebLogic Deploy Tool is used to create the domain image from a model file. Details about the tool and the model file format can be found in its GitHub project:
+### WDT Model File and Archive
 
-https://github.com/oracle/weblogic-deploy-tooling
+This sample includes a basic WDT model, simple-topology.yaml, that describes the intended configuration of the domain within the Docker image. WDT models can be created and modified using a text editor, following the format and rule described in the README file for the WDT project in GitHub.
+
+Another option is to use the WDT discoverDomain tool to create a model. This process is also described in the WDT project's README file. A user can use the tool to analyze an existing domain, and create a model based on its configuration. The user may choose to customize the model before using it to create a new docker image. 
+
+Domain creation may require the deployment of applications and libraries. This is accomplished by creating a zip archive with a specific structure, then referencing those items in the model. This sample creates and deploys a simple ZIP archive containing a small application WAR. That archive is built in the sample directory prior to creating the Docker image.
+ 
+When the WDT discoverDomain tool is used on an existing domain, a ZIP archive is created containing any necessary applications and libraries. The corresponding configuration for those applications and libraries is added to the model.
 
 ### How to Build and Run
 
-**NOTE:** The image is based on a WebLogic image in the Docker store: store/oracle/weblogic:12.2.1.3 . Verify that you have access to download this image.
+**NOTE:** The image is based on a WebLogic image in the Docker store: store/oracle/weblogic:12.2.1.3 . Download this image to your local repository before building the image.
 
 The WebLogic Deploy Tool installer is required to build this image. Add weblogic-deploy.zip to the sample directory.
 
@@ -26,9 +32,10 @@ To build this sample, run:
 
     $ docker build \
           --build-arg WDT_MODEL=simple-topology.yaml \
+          --build-arg WDT_ARCHIVE=archive.zip \
           -t 12213-domain-wdt .
 
-This will use the model file in the sample directory.
+This will use the model file and archive in the sample directory.
 
 To start the containerized Administration Server, run: