i need a simple dynamic AI system ?

more than half the time unity will not connect with the asset store , and plus i thought i would ask some Advice

I have a friend who has "simplePath" and i had a play with that. it uses a messaging system to tell components when to update, but trying to pull every thing apart so i can just get the key parts, i found to be tricky , cause i need to be able to able to re-arange the code to fit in with my code , which after 3 attempts i was not able to do.

So i any one has experence with any good ai sytems could you point them out please