A Deployment Unit defines the set of objects to be deployed together.
Only Main objects, File objects and Business process Diagram objects are available for selection in a Deployment Unit
To deploy the objects defined by a Deployment Unit, you may use the Application Deployment tool.
Typically, for an application that has a front office, back-end and Services layer, you create a Deployment Unit for each, but you are free to define the ones you need.
In the LightCRM Sample, what you need to deploy is clearly the Home (LightCRM Web), the Services required for the LightCRM Android and iOS App, and the Android and iOS App itself.
If you want to deploy the Web and the Services separately (for example to https://example.com/Main and https://example.com/Services), you now can define two Deployment Units: The 'Site' with the Home object (and its called objects) and the 'Services' defined by the LightCRM object.
Then, deploy each. To Deploy a Deployment Unit you have two options: Right-click on a Deployment Unit (which opens the Application Deployment Toolwindows ready to deploy the selected Deployment Unit), or open Build-> Application Deployment and then select the desired Deployment Unit.
Deployment Unit object is available since Genexus 15 Upgrade 10.