LevelMesh missing from FPS and Platformer Tutorials

I've been trying to learn how to use Unity from a handful of tutorials, and I was really excited to start with one of the more advanced lessons. However, I immediately get stuck on the opening of both the FPS and 3D platformer tutorial because the LevelMesh is missing. After importing the assets into Unity each time, I was able to locate the proper folder, but not the file. The file doesn't show up when I look at the folder in Windows Explorer, and I've re-downloaded both ZIP folders for both projects twice. Is there any other explanation for why the levels are missing?