Preliminary explanation of process enactment

doc/process_enactment.rst

@@ -1,14 +1,33 @@
 Process Enactment
 =================
 
-Supports enactment of process models
+A final operation that is useful to modellers, is the enactment of process models.
+When enacting a process model, a series of operations on models is automatically executed.
 
 Finding process models
 ----------------------
 
-Query with model_list
+To find process models, you can easily query the Modelverse for models that conform to *ProcessModel*.
+All such models can be executed, given that the models and operations they refer to, exist.
 
 Enacting process models
 -----------------------
 
-How to
+To enact the process model, such as *query_state_space*, you must execute the following operation::
+
+    >>> process_execute("query_state_space", "my_", {})
+
+There are three parameters to this function, the first obviously being the name of the process model, as shown in *model_list*.
+The second parameter is a prefix for the models used in the process model.
+When executing a process model, data is processed and produced.
+By providing a prefix, the names of these models are first prefixed with the prefix, before they are resolved.
+As such, it becomes possible to execute a process in different contexts.
+
+.. note::
+   This behaviour is likely to change in the future, with the process taking a mapping from the terms in the process model, to actual names.
+
+The third parameter is a dictionary of callbacks.
+For each activity, it is possible for users to define a callback function.
+This function will be invoked when the specific activity is executed.
+For example, a manual operation will require user input, for which this callback function can then serve.
+Further details are given later.