Add docs section on pre change transformer in the variables tutorial

docs/tutorials/creating-atoms.md

@@ -11,6 +11,6 @@ There are several ways of creating Atoms in your project. The recommended way is
 
 ![creating-atoms](../assets/creating-atoms/atoms-creation.gif)
 
-Another way to create Atoms is to select `Unity Atoms` in the context menu. The items are listed by category and by type. Custom Atom types created using the `Generator` (introduced by a later tutorial) also appear in this menu.
+Another way to create Atoms is to select `Unity Atoms` in the context menu. The items are listed by category and by type. Custom Atom types created using the `Generator` also appear in this menu (see the dedicated [generator tutorial](./generator.md) for more info on the generator).
 
 In the following tutorials this is simply referred to as "creating an Atom" using any of the above mentioned techniques.

docs/tutorials/variables.md

@@ -87,6 +87,18 @@ The `Developer Description` is a text describing the Variable in order to docume
 
 `Changed` and `Changed With History` are explained in the [Events](./events.md) tutorial.
 
+## Clamp health changes
+
+Before we continue we can create a pre change transformer to clamp the `Health` between 0 and the value of `MaxHealth`. Go ahead and create an `ClampInt` function and rename it `ClampHealth`. Set min to 0 and max to `MaxHealth`. 
+
+![clamp-health](../assets/variables/clamp-health.png)
+
+Add it as a pre change transformer to the `Health` variable:
+
+![int-variable_clamp-health](../assets/variables/int-variable_clamp-health.png)
+
+The value of `Health` will now be clamped between 0 and the value of `MaxHealth`.
+
 ## Assigning Atoms
 
 Atoms can be assigned using the Unity Inspector. Assign the Atoms on the `PlayerHealth`  like this: