Zombie script

Hello, i am currently making a zombie video game and i need some help. I have little java experience and am learning now but am not far at all yet. i need just a few scripts and some advice would be very useful. i have purchased a zombie character. it came with animations but it just loops through idle, run, attack and die. The thing is, is that it is named under 1 animation. I would like to make it so when you comes within circle1 = he runs, circle2 = attacks (and causes my life to go down) and 3, die when i shoot him. Should i add in the idle and run animation? or is there a way to add a script to activate the animations under the 1 animation. thank you for your time it is very much appreciated.

Here you go.
http://unity3d.com/support/documentation/Components/class-Animation.html

I would advice you to start doing a bunch of tutorials before you do your own thing, you will get much better results =)