Added more property help docs

app/private/docs/property/constant.md

@@ -0,0 +1,33 @@
+# Constants
+
+Constants are properties that store some primitive value in a variable name for use in other calculations.
+
+Unlike attributes, constants can store more than just numbers:
+
+- Arrays: `[1,2,3,4]`
+- Text strings: `'I am a cat'`
+- Numbers: `3.14`
+- Boolean values: `true`, `false`
+- Dice rolls: `1d20 + 2`
+
+Constants just can't use other variables in their calculations.
+
+### Overriding constants
+
+If multiple constants have the same variable name, only the last active constant in the [character tree](/docs/tree) will be used as the definition for that variable name.
+
+This can be used to re-write the value of some constant by ensuring there is a new active constant later in the sheet.
+
+---
+
+### Name
+
+The name of the constants
+
+### Variable Name
+
+The name used to refer to the constant in calculations. Must start with a letter and be made up of only letters and numbers without spaces, symbols, or punctiation.
+
+### Value
+
+A [calculation](/docs/computed-fields) of the final value of the constant.