C# Transform modification.

So, I'm a bit stumped here, I know that to do this in C# you have to go about creating a new Vector3, but here's my code.... not really that easy..

  public void createNPC(string name, int maxHealth, int expReward, int maxDamage, Vector3 position) {
        // Instantiate game object here
         GameObject npcGameObject = GameObject.CreatePrimitive(PrimitiveType.Cube);
         NPC npc = new NPC();
         npcList.Add(npcGameObject, npc);
         npcGameObject.transform = position;

I can't really create a new(position), so I'm not sure how I would go about this...