diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n3/textbook.en.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n3/textbook.en.md
index eefe6ae6b..f893b9693 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n3/textbook.en.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n3/textbook.en.md
@@ -12,5 +12,60 @@ lessons:
 
 #### Brainstorming to structure a theme "Electromagnetism" : level 3
 
---------------------------------
+--------------------------------------
+
+### Foreword
+
+This step is important, because it will be the 
+**first tree structure of the filesystems and subfiles in which the contributors will work**. 
+This tree structure may evolve, but it is less agile than the educational contents
+themselves. In themselves, the titles of the chapters and sub-chapters are less important.
+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?
+
+Chapter titles should be words from everyday life. 
+
+#### To participate
+
+The different proposals are numbered: they start with:
+[BRST-EMG1-number]: Title <br>
+_BRST-EMG1 for Brainstorming STructure ElectroMaGnétism level 1)_
+
+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*
+
+To **react to an existing proposal**, add your comment after the others
+starting with three initials in brackets representing you:
+(CLM): previous comment
+*(my initials): my comment*
+
+_or send an email specifying:_
+_the reference [BRST-EMG1-number], the my 3 initials and my comment_
+_(+ a title if it's a new proposition)_ 
+
+To **communicate my proposals**, either:
+* directly on the GitLab m3p2 with your login/password: <br>
+if you are not there already, go to https://gitlab.m3p2.com/brainstorming-123-electromagnetism, <br>
+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
+ (+ 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 
+
+----------------------------------------
+
+### Brainstorming