Dont Understand this error,Dont Understand what this means

‘UnityEngine.Component.GetComponent()’ is a ‘method’, which is not valid in the given contact

Here is how you can use GetComponent. Error can also come from your incorrect C# syntax:

MyScript myscript = myGameobject.GetComponent(typeof(MyScript)) as MyScript;  
MyScript myscript = myGameobject.GetComponent<MyScript>();

You can also refer to the manual: Unity - Scripting API: GameObject.GetComponent