reference to a gameobject

//refere a gameobject from the unity editor

Public GameObject ObjectName; //make sure this is public because you will need to assign it in the inspector


Void Start()
{
	//lets say you want to disable the gameobject but want to enable later.
    //you can do this a few ways, one of those ways is to use a bool, and the other is just to do it on the spot, we are going to do it on the spot.
    ObjectName.SetActive(false); //this will disable the gameobject
}
//lets say you want to enable it through a fuction.
public void Yourfunction()
{
	//you can start this function many ways, through a button, from another script or from this 1.
    //we are going to do it from this 1.
	ObjectName.SetActive(true);
}

//lets say if the player clicks 1 than it will get enabled.

public void Update()
{
	if(Input.KetKeyDown("Alpha1"))
    {
    	//this will check if the player clicks 1 if so it will call the function that sets the object to be enabled.
    	YourFunction(); 
    }
}

// use the keyword "this"

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