diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n4/textbook.en.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n4/textbook.en.md
index 5b654a723..87cdc2ff1 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n4/textbook.en.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n4/textbook.en.md
@@ -22,22 +22,25 @@ They can be changed easily, they are not the structure.
 
 #### Advice on how to structure this level
 
-At this first level, think:<br>
-What knowledge on this topic is useful in everyday life or for understanding future technologies?<br>
-What worries them or scares them?<br>
-What amazes and amazes them?
+These are **our lectures, restructured and redesigned together**. 
 
-Chapter titles should be words from everyday life. 
+##### The blocks
+
+In this level 4, the **blocks** are important because they **allow to differentiate the students**
+according to different specialties. Later we can associate a metadata in the file, 
+to identify the blocks and propose specific pedagogical circuits according to the wishes of each student.
+
+So use the blocks to **target different specializations** within this level 4. 
 
 #### To participate
 
 The different proposals are numbered: they start with:
 [BRST-EMG1-number]: Title <br>
-_BRST-EMG1 for Brainstorming STructure ElectroMaGnétism level 1)_
+_BRST-EMG4 for Brainstorming STructure ElectroMaGnétism level 4)_
 
 To **add a proposition, create it** between 2 propositions, or in the following (following 
 the logic of the proposition). To do this, start with: <br>
-*a new [BRST-EMG1-number] + (three initials in brackets representing you) + Title*
+*a new [BRST-EMG4-number] + (three initials in brackets representing you) + Title*
 
 To **react to an existing proposal**, add your comment after the others
 starting with three initials in brackets representing you:
@@ -45,7 +48,7 @@ starting with three initials in brackets representing you:
 *(my initials): my comment*
 
 _or send an email specifying:_
-_the reference [BRST-EMG1-number], the my 3 initials and my comment_
+_the reference [BRST-EMG4-number], the my 3 initials and my comment_
 _(+ a title if it's a new proposition)_ 
 
 To **communicate my proposals**, either:
@@ -54,14 +57,14 @@ if you are not there already, go to https://gitlab.m3p2.com/brainstorming-123-el
 and at the end of the page, in the green box click on "Edit this course".
 * on the google drive m3p2 project in the document Brainstorming-1-electromagnetism.docx.
 * or send an email to ... specifying: <br>
-the reference [BRST-EMG1-number], then the 3 letters that identify me (my initials) and my comment
+the reference [BRST-EMG4-number], then the 3 letters that identify me (my initials) and my comment
  (+ a title if it's a new proposition) _
 
 The Gitlab will be kept up to date with your proposals, also translated into French and Spanish. <br>
 _(This is not required, but if you can also make your contribution in English, but also in_
 _French or Spanish, this will ease the translation work)._ <br>
 This page at this level can be viewed in a multilingual version at: <br>
-https://m3p2.com/polyglot/brainstorming-pedagogical-teams/synthesis-structuring/electromagnetism/n1 
+https://m3p2.com/polyglot/brainstorming-pedagogical-teams/synthesis-structuring/electromagnetism/n4 
 
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