In order to integrate Diagramming for WinUI into your Visual Studio project, select the Manage Nuget Packages from Project menu:

Open the Browse tab, and enter MindFusion.Diagramming.WinUI in the search field. Select the MindFusion.Diagramming.WinUI package and click Install.

Once the package is installed, you should be able to add components from the library to your UI (Diagram, NodeListView, etc).