How can i Learn Basics of Rain AI

Greetings ,

I try to make my enemy stand in idle and when player gets insight then play run animation and go near to player and with making a specific distance then stop and attack , and when it's attacking arm trigger collide with my player then cause damage to player , or when player shoots bullet to enemy and enemy collide with bullet play a simple animation and destroy with some particle effects , that's all .

I used nav mesh agent and trying to make own ai ref. script , well i probably done that and nav mesh agent have problems , i described in previous question. Someone suggests me to use Rain AI and says it's very easy , But there are not any basic start tutorials about rain ai , not even on there own website ,Rival Theory just post tutorials of advance or example work ,

I can't able to move my enemy and use animations , i don't know about behavior tree and dont know how to use them properly ,

Is there any good tutorial about Rain AI to understand it's work with basics , i am getting too late to complete my 2nd project , hope it will make my game development easier . Thanks .