How to set up turret follow spawned actors?

Hi, I tried to make a turret, that will follow spawned actors ( spheres ) but nothing happens , I tried a tutorial but the turret just start rotating in the first 1-2 seconds to a random location and nothign happens if I spawn the actors. (more than one actor, and follow the closest, or the one in range) tower wars map.

Here are the blueprint I tried:

The Turret, is the top part of my tower, that should rotate, it has a socket in front if it, and the Eneemy is a variable refering to the objects I want to spawn.