Can't put gameobject into prefab

Can anyone give me solutions for this problem, I have a target gameObject that i need so that the enemy follows the player. When i try to put the player gameobject in the target slot it wont allow me to. How can I instantiate gameobjects with the target gameobject still attached.

ps. sorry if my english is not that good.

 

Prefab Assets cannot reference objects in the scene. You'll need to have some script assign the reference to the player when you instantiate the enemy Prefab.