Assault Waves

Assault waves are largely handled by the game automatically. You only have to set up a few things.

First of all you should set up some spawns for the Cops:
Place some SpawnEnemyDummy elements around your map, preferably in areas the player can’t see. You can even set animations in the Spawn Actions for things like climbing up a ledge or repelling down from somewhere in case the spawn is in a visible area. The other settings don’t matter in this case.
To make your spawns more organized, should group up spawns with a SpawnEnemyGroup element. In there you can even toggle specific types of enemies for the spawn group and increase the interval if needed. For regular assault spawns you can enable everything except for single_spooc and Phalanx.

To activate spawn groups, you need a EnemyPreferedAdd Element. Select the spawn groups in there and execute it when you need them enabled. You can add more spawn groups like this at any point in the heist, for example if the player opens a new area. Additionally you can use EnemyPreferedRemove to disable spawns.

Next you need to set-up Difficulty Elements. Those determine the intensity of your assault phases. It has to be above 0 for enemies to spawn. You can increase or decrease the difficulty intensity any time.

Lastly, make sure the Whisper State is set to disabled, otherwise the game will not start any assault waves and remain in stealth mode. Simply execute a WhisperState Element with the Whisper State setting off.

You can use a GlobalEventTrigger Element with police_called to execute the whisper state and set the difficulty to start the police assaults when a NPC calls the cops, but you can also choose different triggers or even execute the elements manually at any time.