AI Follow Player script

Hi, i am new.

I am making a game i unity and i am trying to make a simple AI that i can use to make an enemy follow the player and damage him. I have tried lots of tutorials, But they seem not to be working. And i was wondering if any of you know how to make one. Can you help me?

 

Did you see this one:

https://unity3d.com/learn/tutorials/projects/survival-shooter/enemy-one?playlist=17144

This tutorial has enemies that follow player and damage him on collision, think that's the one you are looking for.