First you need to install the GMF from eclipse.org.
http://download.eclipse.org/modeling/gmf/downloads/drops/R-2.0-200706210000/index.php
The oAW gmfadapter is available from the oAW updatesite:
http://www.openarchitectureware.org/updatesite/milestone/site.xml
(Go to the project's homepage and find the current location if either of the sites don't work)
Restart your Eclipse workbench when Eclipse asks you to do so.
You need to import one project into your workspace It is called "org.openarchitectureware.adapter.gmf2". You can do that using the import wizard. Do a right click in the Project Explorer and choose Import... Now select "Plug-ins and Fragments" from the Plug-in development section. Import the bundle as a project with source folders.
Next, open your .gmfgen file and set the following properties in the your GenDiagram Element:
Set Validation Decorators in the section "Diagram" to true
Set Validation Enabled in the section "Diagram" to /org.openarchitectureware.adapter.gmf2/templates
Now, select your Gen Editor Generator and set the following properties:
Set Dynamic Templates to true
Set Template Directory in the section "Diagram" to true
Right-click into the gmfgen editor and choose the "Add extension model..." action. Browse your file system and got to your eclipse installation directory. Navigate to plugins/org.openarchitectureware.adapter.gmf2.extensionmodel_1.0.0\model and choose oawGmfExtension.ecore. Select the CheckContainer when asked for the Root Class
In the CheckContainer element you have to set the diagram from your gmfgen. Normally there is just one to select. You can also choose whether you'd like to run the validation in a cyclic mode or not. The cycle time attribute is the time in ms. Default is one second
Finally you can add a list of Check Elemens. In each of them you have to specify the plugin ID and the relative path to the check file from the plugin root
For more information on checks, please refer to the Check documentation Xtend/ Xpand/ Check Reference