My LevelTemplate scene crashed after this lecture. Took me 40 minutes to understand that I had to put materials on the desk so it won’t crash.
So if anyone else is having this problem- try putting materials on the surfaces. (click on the desk and you’ll see headlines “surface 1”, “surface 2”, “surface 3”. put the materials there.)
I used dark wood for both surfaces 1 and 2, and for the 3rd surface- metal.
(you have the materials ready in the assets’ “Materails” folder)
Hope I could help someone 
