[AI] How do I make units/heroes move around and attack?

[Azndragon]

I've been mapping for a few years but never have I done any work using Units (The units trigger section).. so now that I map alone I have a few questions I want to ask!

How do I make Computer Controlled units move around by themselves?
So here's the map I'm trying to make..

Zombie Survival: Dark House
If anyone here has played combat arms recently, you will find that there is a new fire team map where you must stay in a house and survive zombie onslaughts.. This map is based on that!

So my questions are:

•How do I make zombies move towards players in the house (not to a point in the house and just stand there but towards all surviving players) and attack the players?

•If a player leaves the house region, how do I make them lose 50 health /second?

•How do I make players re-spawn after each round? (5 Minutes)


Thanks for reading, please help me out!


EDIT: Also one more thing, how can I make the zombies attack doors that are passive/neutral?