diff --git a/configuration/micro_kernel_trait.rst b/configuration/micro_kernel_trait.rst
index 9a576fdc10e..3d9291570d7 100644
--- a/configuration/micro_kernel_trait.rst
+++ b/configuration/micro_kernel_trait.rst
@@ -126,6 +126,14 @@ your ``composer.json`` file to load from there:
         }
     }
 
+Before going any further, you need to regenerate the autoload files! Your changes in the "autoload"
+section of the ``composer.json`` file will not be in effect until you run the following command:
+
+.. code-block:: bash
+
+    $ composer dump-autoload
+    
+    
 Now, suppose you want to use Twig and load routes via annotations. Instead of
 putting *everything* in ``index.php``, create a new ``app/AppKernel.php`` to
 hold the kernel. Now it looks like this::