Add a little extra documentation that would have helped us.

docs/general/04_detail_module_concept.rst

@@ -377,6 +377,8 @@ Focusing on the source and header files, generally, the tool generates:
 * One source-header pair describing a class for each interface implementation
   in the module: ``${IMPLEMENTATION_ID}/${INTERFACE_NAME}Impl.{cpp, hpp}``
 
+.. _moduleconcept_modclass:
+
 The module class
 ----------------
 
@@ -399,7 +401,10 @@ a few notable members:
   - reference to the interface implementation;
 * For each interface requirement:
   ``std::unique_ptr<${INTERFACE_ID}Intf> r_${REQUIREMENT_ID}`` - use this to
-  trigger commands or subscribe to variables on the provider.
+  trigger commands or subscribe to variables on the provider. If 1 is used
+  for ``min_connections`` and ``max_connections`` in ``required`` in the module's
+  manifest a pointer is given as an argument as shown, otherwise it's an
+  array (std::vector) of pointers.
 
 The header file contains designated areas where further members or other
 definitions can be added.

docs/tutorials/new_modules/index.rst

@@ -110,6 +110,15 @@ command `command_tutorial` that can be called by another module and will
 just always return the string "everest" as result. We will later give some
 ideas how to extend this minimal example.
 
+In C++, the interface is an object class that wraps the publish and
+subscribe of the MQTT topics of the interface.
+
+The MQTT topics of an interface are either commands or variables.
+It comes in two forms, depending on if you are using it or implementing it.
+
+- Implementation handles commands and publishes variables.
+- Interface offer subscribing to variables and invokes commands.
+
 We store the following interface configuration in form of a .yaml file in
 `$EVEREST_TUTORIAL_DIR/interfaces/interface_tutorial_module.yaml`:
 
@@ -238,6 +247,11 @@ its interface implementations.
 Among others, you'll furthermore find the module's configuration and a pointer
 to the interface implementations.
 
+Note: After you have built on your module's autogenerated code, you may well
+find you need to change the manifest but don't want to regenerate these files.
+Changing the manifest may change the arguments your modules contructor is
+called with by other auto generated code, so you have to know how to change
+it. Please refer to the :ref:`the module class in the module concept <moduleconcept_modclass>`.
 
 **interface_impl_tutorial_module/interface_tutorial_moduleImpl{.hpp,.cpp}:**
 For each interface implementation (here, only a single one is defined), the