Mono Hooks
Mono Hooks save the effort of writing boilerplate code to raise Atoms Events from Unity's Event Functions.
A great use for Mono Hooks in our example would allow us to remove the Harmful.cs script created earlier. We could instead attach a OnTrigger2DHook.cs to the Harmful GameObject and toggle on Trigger On Enter like this:

We could then create a Collider2DAction called DecreasePlayersHealth.cs and add it to a Collider2D Event Reference Listener attached to the Harmful GameObject:
public class DecreasePlayersHealth : Collider2DAction
{
public override void Do(Collider2D collider)
{
if (collider.tag == "Player")
{
collider.GetComponent<PlayerHealth>().Health.Value -= 10;
}
}
}

There is much less code written and the responses can be edited in the Editor.
That is it! We have covered the most fundamental pieces of Unity Atoms and a way to use them with Unity's built-in functionality. You can get far with these alone, but there are many more features in Unity Atoms and the subpackages to explore.