The world's of Unity are made up of individual pieces called "GameObjects". Each game object has a collection of components that dictate its behavior. Using programming (scripting) these behaviors can be expanded and manipulated.

In the example script we are manipulating a property on the rigidbody. We are applying a force based on keyboard input.

more information about rigidbody https://docs.unity3d.com/ScriptReference/Rigidbody.html

more information about input

https://docs.unity3d.com/ScriptReference/Input.html