diff --git a/developer_manual/app_development/intro.rst b/developer_manual/app_development/intro.rst
index 6f034836e..6fde12b4f 100644
--- a/developer_manual/app_development/intro.rst
+++ b/developer_manual/app_development/intro.rst
@@ -13,6 +13,35 @@ After :doc:`you've set up the development environment <../getting_started/devenv
 
 Then create a skeleton app in the `app store <https://apps.nextcloud.com/developer/apps/generate>`_. This doesn't publish anything on the appstore yet, it just gives you a download.
 
+Edit an existing app
+--------------------
+
+Alternatively, if you would like to contribute to an existing app instead of creating a new one, first :doc:`set up the development environment <../getting_started/devenv>`, then create an `apps-extra` folder in the Nextcloud root directory::
+
+    cd /var/www/nextcloud/apps-extra
+    
+You can then configure Nextcloud to run apps from this directory, by changing your `app_paths` system config in your `config.php`
+
+    'apps_paths' => 
+    array (
+      0 => 
+      array (
+        'path' => '/var/www/html/apps',
+        'url' => '/apps',
+        'writable' => false,
+      ),
+      1 => 
+      array (
+        'path' => '/var/www/html/apps-extra',
+        'url' => '/apps-extra',
+        'writable' => false,
+      ),
+    ),
+    
+Finally, clone the app to which you would like to contribute inside the `apps-extra` folder. For example:
+
+    git clone https://github.com/nextcloud/cookbook.git 
+
 Enable the app
 --------------
 The app can now be enabled on the Nextcloud apps page.