Killable NPC who can kill player

I have learned the basics to C# scripting. These include; Variable, Strings, Arrays, Conditions, Operators and Loops. I need to make an NPC which can take damage from weapons and can cause damage to the player. Which of the basic skills would I need to use to do this? Is there anything else I need to know to do this?

I have a fully working script available on another answer here !

[JS. Convert to CS if you need]
Just apply those scripts to the NPC, remove the animations like walking, attack, or whatever fits your NPC’s needs, and you will be on your way . Please do keep in mind that you will need to do some tweaking, but, essentially, it’s no different than an Enemy. They are all entities.


URLS–
Motor: ZombieMotor - Pastebin.com

Intelligence: Zombie AI - Pastebin.com

Animator+Controller: ZombieController - Pastebin.com