Introduction

The Scene view is where you'll manipulate and change things.
When you enter Play Mode "▶", the Scene view changes into the Game view for testing.
Everything in your game is called a GameObject.
The Hierarchy is where you organize GameObjects.
When you select a GameObject in the Hierarchy, you'll see it's components in the Inspector.
Components contain properties that give a GameObject specific functionalities.
Prefabs are templates for GameObjects with preset components. They are stored as assets.

A prefab is an asset that acts as a template of a GameObject. From the prefab, you can create multiple copies, called instances. A change to the prefab asset causes all of its instances to change as well.

GameObjects and Components

GameObjects is an object that lives in your scene. A GameObject is in fact only defined by its Components, think of it more as a container for Components.

Components are the building blocks that define a GameObject. Scripts are also components and are inherited from MonoBehaviour class.

Example:

GameObject - Cube
- Component - Transform
  - Variables - Position, Rotation, and Scale

Components
Rigidbody and * Collider components are for physics
Mesh Filter and Mesh Renderer components are for 3D geometry