If you quickly want to explore the terrain and visit the bonus level via the Terrain hole, a quick and easy way of getting a working third-person controller is to visit the Asset Store and get the free Invector LITE package. Once imported, remove Main Camera from your scene, and drag ThirdPersonController_LITE and vThirdPersonCamera_LITE Prefs into it. Select ThirdPersonController_LITE and, in the Inspector window, set Jump Height to 10. This should be sufficient to allow the character to jump up and over the raised circle around the entrance to the Terrain hole so that they can get to the bonus level:
Figure 5.51 – Adding the Invector LITE free third-person controller to the scene