Import a ready 3D airplane model into an existing C# WPF project

I seek assistance with importing a ready 3D airplane model into an existing WPF project and replace the "flying" 3D cube that I have in that project. You may use any method to import the airplane model such as Helix Toolkit, ASSIMP or others. Please refer to the .mp4 videos that show both the current project demo as well as the airplane model. Both the WPF project files and the .dae or .obj files of the airplane will be provided.