To install your application on the device please do the following:
Open the Windows Device Portal for your IoT device.
In the Apps menu add your UWP App Package, certificate and dependency App Packages(s).
Deploy the app.
The application will now be visible on the list of applications on your device.
To add the application as a part of your device image follow the instructions outlined in the manufacturing guide.
A sample provisioning package with UWP application can be found in our GitHub repo.