To install your packaged applications on your machines there are several ways to do it.
Configuration Group (Registration)
You add the Configuration group an application role. So your machines are registering to your XOAP portal, receive their DSC configuration and the applications.
Download the application configuration for the specific app you want to install. The downloaded file is a .ps1 Script which you can easily run on your machine.
You can also download the script for a Group which contains your application configurations you have added.
Just like the configuration group the application Role which are containing the groups can also be downloaded.
Now its up to you to roll out the .ps1.