How to Create BT for AI 2nd character to follow main like Final Fantasy 15

Hello everyone,

I have an AI 2nd player and I’m trying to get it to run like Final Fantasy15 through Behavior Tree.

Basically the 2nd player always follows the main character when the main starts moving.
Stays within a radius in movement and Idle
When main is not moving the AI can moveTo a location within a radius and idle there and kind of loop this if the main is idling for long period when player is AFK.

Been trying to figure it out. Not going so well.
Many thanks to any help!!!