Finite State Machine or another good approch for Decision system

Hi,

i have no code to for now currently i am looking for a good and easy material using FSM and/or something similar to get me started.

What i am planning to make is a IRC AI RPG BOT to take decision upon what is going on and considering users responses.

So for example: Player A target and begin attack.

So upon the state of being targeted the bot will have a response to it for example, set trap for player A.

OFC this is just hipotetical examples...

So i was thinking on how i could start such states and take actions upon it and aswell some sort of priority system... but i am kinda stuck of where to start at...

i was trying to find some simple and good material around to get me started but so far i havent found anything perhaps i am not using the right keyword for my search

but if any of you have something that could get me started i would appreciate