Updated Writing the handlers (markdown)

Writing-the-handlers.md

@@ -1,3 +1,11 @@
 # Writing the handlers
 
-Now you have to implement each handler. You need to inherit from WSF_SKELETON_HANDLER (as ORDER_HANDLER does). This involves implementing a lot of deferred routines. There are other routines for which default implementations are provided, which you might want to override.
+Now you have to implement each handler. You need to inherit from WSF_SKELETON_HANDLER (as ORDER_HANDLER does). This involves implementing a lot of deferred routines. There are other routines for which default implementations are provided, which you might want to override. This applies to both routines defined in this class, and those declared in the three policy classes from which it inherits.
+
+## Implementing the routines declared directly in WSF_SKELETON_HANDLER
+
+TODO
+
+## Implementing the policies
+
+TODO