As shown in the picture, horde spawns at 200m/ whatever distance silently, a single silent noise pulce attracts all the spawned zombies to go in that direction until they reach the other side/ a set distance then de-spawn to replicate a roaming horde event.

The player gets no warning and is entirely random within a set timer, similar to the settings already. : https://imgur.com/a/XgAVdiy <--- here