Need help with this error

This is the unityscript code i have

 #pragma strict

function Start () {

}
var prefabBullet:Transform;
var shootForce:float;

function Update () 
{
	  if(Input.GetButton("Fire1"))
	{
		var instanceBullet = Instantiate(prefabBullet, transform.position, Quaternion.identity);
		instanceBullet.rigidbody.AddForce(transform.forward * shootForce);
	}
}

and here is the error message

UnassignedReferenceException: The variable prefabBullet of ‘Shoot’ has not been assigned.
You probably need to assign the prefabBullet variable of the Shoot script in the inspector.
UnityEngine.Object.Internal_InstantiateSingle (UnityEngine.Object data, Vector3 pos, Quaternion rot) (at C:/BuildAgent/work/812c4f5049264fad/Runtime/ExportGenerated/Editor/UnityEngineObject.cs:44)
UnityEngine.Object.Instantiate (UnityEngine.Object original, Vector3 position, Quaternion rotation) (at C:/BuildAgent/work/812c4f5049264fad/Runtime/ExportGenerated/Editor/UnityEngineObject.cs:53)
Shoot.Update () (at Assets/Shoot.js:15)

Explain
inb4 formatting sucks

The problem is just as the error says. ‘prefabBullet’ is uninitialized. Click on the game object in the hierarchy this script is attached to, then drag the prefab for the bullet onto the ‘prefabBullet’ variable in the inspector. For the sake of cleanness, I’d also declare the bullet as a GameObject rather than a Transform.

i love u<3