The namespace – highlighted in blue

The namespace is simply an organizational construct. It helps organize parts of code. Don't worry too much about it now. We won't need to create them anytime soon. All we will need to know for now is how many namespaces we are using in our script.

In our script, we can see these two lines:

using UnityEngine; 
using System.Collections; 

The preceding two lines simply mean that our script will be using the UnityEngine and System.Collections namespaces, and we will have access to all parts of these libraries. These two namespaces are added to any new C# script by default, and we will use them in most of our cases.