diff --git a/docs/gettingstarted.rst b/docs/gettingstarted.rst
index 71d3ea34f..a673f9402 100644
--- a/docs/gettingstarted.rst
+++ b/docs/gettingstarted.rst
@@ -1,26 +1,6 @@
 Getting started
 ====================
 
-.. _installation:
-
-Installation
-----------------
-
-- Open a shell session
-
-.. type-along:: Optional: install the Rougail library in a virtual environment
-
-- install the virtual environment: `python -m"venv' .venv`
-- activate it `./.venv/bin/activate` (or `.venv\Scripts\activate.exe` under windows)
-
-.. type-along:: Rougail's library installation
-
-You can use the `pip` python installer, here is the install command:
-
-.. code-block:: text
-
-    pip install rougail
-
 What is a consistency handling system ?
 ------------------------------------------------
 
diff --git a/docs/index.rst b/docs/index.rst
index 0183508aa..b4bcb56ab 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -87,6 +87,11 @@ Explained differently, Rougail allows you to easily implement an integration of
 
    developer
    documentation
+
+.. toctree::
+   :hidden:
+
+   install
    
 .. rubric:: Index page
 
diff --git a/docs/install.rst b/docs/install.rst
new file mode 100644
index 000000000..e1c6799aa
--- /dev/null
+++ b/docs/install.rst
@@ -0,0 +1,23 @@
+.. _installation:
+
+Installation
+===============
+
+Activate you virtual environment
+------------------------------------
+
+- Open a shell session
+
+- install the virtual environment: `python -m"venv' .venv`
+- activate it `./.venv/bin/activate` (or `.venv\Scripts\activate.exe` under windows)
+
+Standard installation
+---------------------------
+
+You can use the `pip` python installer, here is the install command:
+
+.. code-block:: text
+
+    pip install rougail
+
+
diff --git a/docs/tutorial/preliminary.rst b/docs/tutorial/preliminary.rst
index 147a53e09..00595bc56 100644
--- a/docs/tutorial/preliminary.rst
+++ b/docs/tutorial/preliminary.rst
@@ -12,7 +12,10 @@ Preliminaries
 .. prerequisites:: Prerequisites
 
     - We assume that Rougail's library is :ref:`installed <installation>` on your computer.
-    - This workshop page corresponds to the tags v1.1_000 to v1.1_011 of :tutorial:`the Git repository <src/tag/v1.1_010>`. 
+    - If you want to follow with this tutorial with the help of the corresponding :tutorial:`Rougail tutorial git repository <>`, 
+      this workshop page corresponds to the tags v1.1_000 to v1.1_011.
+      
+..       of :tutorial:`the Git repository <src/tag/v1.1_010>`. 
 
 Making a structure file 
 -------------------------
@@ -140,8 +143,8 @@ So let's define a variable with a description -- **and a default value**
 
     A default value has been set, great. Now how do I assign a value to a variable?
 
-How to set a value
-----------------------
+The different rougail roles and the default values
+------------------------------------------------------
 
 So far we have only talked about the one that writes the :term:`structure files <structure file>`\ . It's *role* is called the integrator's role.
 
@@ -166,9 +169,6 @@ Now we will talk about the one that defines the values. It is called the operato
 
         The user :term:`value`\ s, that is the values that have been set by the operator, are of course type validated. The type validation is driven by the definitions in the :term:`structure file <structure file>`.
 
-Values are mandatory
--------------------------
-
 It is the operator's responsibility to set the user datas variables values.
 The operator does not handle the structure files, 
 he is responsible of other files called the :term:`user data file`\ s. 
@@ -185,6 +185,8 @@ he is responsible of other files called the :term:`user data file`\ s.
         The consistency field is outside of the user datas scope. 
         The consistency is handled in the :term:`structured datas <structured data>`\ 's scope.
 
+.. important:: If user datas are not set, default values are mandatory, otherwise Rougail will raise an Error. 
+
 .. exercise:: Folder structure update
 
     Now we add a :file:`config/config.yml` file in our project::
@@ -317,7 +319,6 @@ We have the list of the possible (authorized) values:
 - `Manual proxy configuration`
 - `Automatic proxy configuration URL`
 
-
 .. keypoints:: Key points progress
 
     Indeed, in the Firefox configuration, it is possible to define several configuration modes, from no proxy at all (`no proxy`) to a kind of automatic configuration mode from a file (`set up proxy configuration from a file`).