how to use class in programming c# with unity?

how to use 'class' in programming c# with unity? 1. 'class' that we created ( example :

Code (CSharp):

1. public class PlayerData

in PlayerData.cs. 2. 'class' exist in unity class library ( example : UnityEngine.Sprite ). what different between using class ? how to understand it ? what i create a 'class'.cs for? how it work? how to learn create a class file and use it? how to use class in unity class library?

 

If you want to use a Class sytem in unity, you can use [System.Serializable] to make tbis happen

Code (CSharp):

1.     [System.Serializable]
2.     public class MyClass
3.     {
4.         public string name;
5.         public int number;
6.  
7.     }
8.  
9.     public MyClass myClass; // makes it visible in inspector

You can put this in any script (just before any methiods such as Start/Update

 

this might help:
https://unity3d.com/learn/tutorials/topics/scripting/coding-unity-absolute-beginner

if you use c#, you are always using classes. They just contain data and functions.