Help with spawning ai

Hey guys, I’m totally new to unreal. I’ trying to set up a situation where as the player is walking, he walks in to a trigger which spawns a demon ai behind some trees who walks across the path in front of the player, until its out of sight where it then despawns. I can’ seem to find how to make this happen or how to set up the blueprint. Anybody out there have some help they can offer?