how to access gameobject in unity script code example

Example 1: how to find gameobjects in unity

using UnityEngine;
using System.Collections;
// This returns the GameObject named Hand in one of the Scenes.
public class ExampleClass : MonoBehaviour
{
    public GameObject hand;    
    
    void Example()
    {
        // This returns the GameObject named Hand.
        hand = GameObject.Find("Hand");        
      
        // This returns the GameObject named Hand.
        // Hand must not have a parent in the Hierarchy view.
        hand = GameObject.Find("/Hand");     
      
        // This returns the GameObject named Hand,
        // which is a child of Arm > Monster.
        // Monster must not have a parent in the Hierarchy view.
        hand = GameObject.Find("/Monster/Arm/Hand");
        
        // This returns the GameObject named Hand,
        // which is a child of Arm > Monster.
        hand = GameObject.Find("Monster/Arm/Hand");
    }
}

Example 2: findobject getcomponent

GameObject.Find("Name of the object you want to access").GetComponent<Name of the Component (Transform,Script,RigidBody,etc..)();
     
     An Example (easy to understand):
     
     GameObject Player = GameObject.Find("Player");
     PlayerController PlayerControllerScript = Player.GetComponent<PlayerController>();
     PlayerControllerScript.run = true;
     
     Another Example:
     
     GameObject.Find("Player").GetComponent<PlayerController>().run = true;

Example 3: how to reference this gameobject unity

// use the keyword "this"

this.SetActive(true);
// the line above will set the GameObject this script is attached to active