Here is a general overview of some of the more important directories in the project.
.
├── data
│ └── workspace.json // an export of a basic Speech Sandbox assistant setup
├── SpeechSandbox // the Unity project
│ ├── Assets // contains all project assets
│ │ ├── _Scenes // all game scenes
│ │ │ ├── Playground // Main game scene
│ │ │ │
│ │ │ │
│ │ │ │
│ │ ├── Prefabs // the games prefabs
│ │ │ ├── CreatableObjects // all objects that can be created
│ │ │ └
│ │ ├── Scripts // all custom game scripts
│ └── ProjectSettings // contains configuration files for the project
For additional help understanding the code you can check out this blog written by Kyle Craig about how to implement this type of speech control in your own projects.