Acces a component on an instantiated object

Well here ou have my problem, I have an instantiated Prefab (BodyPart) by script that appears when i hit the play. This prefab it's instantiated by a Manager script attached to an empty GameObject who has all the game inside. Now, this Prefab (BodyPart) has a script attached call "Follow" as component and it's a C# script similar to "SmoothFollow". I know for sure that this script begins when i instantiate the prefab because y put a Debug.Log on start and works grate. What i need it's to tell this Script who has to Follow, in other words, the Target. But when i'm on Manager script with the instantiated prefab y make GetComponent and then try to access a public function on the script and i can't. HELPE ME PLEEEASE!!

Here you have my code

Manager Script

public class Manager : MonoBehaviour {

void Start () {

prefabTail = GameObject.Instantiate (Resources.Load("BodyPart",typeof(GameObject)))as GameObject;

prefabTail.transform.parent = this.transform;

prefabTail.GetComponent<Follow>();

    prefabTail.FunctionIWantToAcces("Bodypart2");// It says NullReference

}

}

Follow Scrpt

public class Follow : MonoBehaviour { void Start() {

}

public void FunctionIWantToAcces(string targetName)
{
    GameObject targetLoaded = GameObject.Find(targetName);
    target = targetLoaded.transform;

    }

}

PD: sory if i have english problems i'm From Argentina we speak spanish :p

It looks like you want to call the FunctionIWantToAcces method on the Follow component, but you are trying to call FunctionIWantToAcces on the Manger component. You should get an instance of the Follow object and call FunctionIWantToAcces on that instance.

void Start () {

    prefabTail = GameObject.Instantiate (Resources.Load("BodyPart",typeof(GameObject)))as GameObject;
    prefabTail.transform.parent = this.transform;

    Follow tailComponent = prefabTail.GetComponent<Follow>();
    tailComponent.FunctionIWantToAcces("Bodypart2");
}