What I did to get this scene.
Place wallpaper in perspective view.
Adjusted grid to fit horizon.
Adjusted viewport properties to set Projection and camera lens length.
Two point perspective seems to work best.
Camera length is 5.
Placed model at 0,0.
Toggle model using gumball, zoom, scale tools to position model against background.
Practice with a simple wireframe shape to begin with.
If you send me a file of your model and scene then I can help you some more.