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 f893b9693..ec85ad51f 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
@@ -22,24 +22,45 @@ This tree structure may evolve, but it is less agile than the educational conten
 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
+#### Advice on how to structure this level 3
 
-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?
+This is the **equivalent of the first or two first years in university**. There is a big jump 
+with the previous level. But we are not limited to a number of hours or pages. 
+We can make a quiet and controlled progression even within this level 3.
 
-Chapter titles should be words from everyday life. 
+The high school is not homogeneous, there are pathways, specialties and options, 
+and moreover the programs also vary according to the country and period. 
+Some mathematical tools of level our N3 can be seen already in high school in some
+countries. Conversely, it is possible that certain points of our level N2, are not 
+seen in high school. **Think these levels 2 and 3 freely and without references in mind**.
+
+Even inside a level, you have to be very progressive, we have the space for that.
+The gap should not be too large from one level to another, so as not to demotivate
+the students. 
+
+##### The blocks
+
+In this level 3, the **blocks** are important because they **allow to differentiate the students**. 
+For example we can make an electrostatic block for students who wish to stop at this level 3
+in electromagnetism. It can be a block with only direct calculations, and the notion of 
+electric dipole. But without Gaussian theorems and the divergence operator, which will
+be put in another block for students who have to prepare the mastery of Maxwell's equations
+of electromagnetism at level 4.
+
+Later we can associate a metadata in the file, to identify then blocks and offer 
+specific pedagogical circuits according to the student's wishes.
+
+So use the blocks to also **target different pre-specialties** within this level 3. 
 
 #### To participate
 
 The different proposals are numbered: they start with:
-[BRST-EMG1-number]: Title <br>
-_BRST-EMG1 for Brainstorming STructure ElectroMaGnétism level 1)_
+[BRST-EMG3-number]: Title <br>
+_BRST-EMG3 for Brainstorming STructure ElectroMaGnétism level 3)_
 
 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-EMG3-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:
@@ -47,7 +68,7 @@ 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-EMG3-number], the my 3 initials and my comment_
 _(+ a title if it's a new proposition)_ 
 
 To **communicate my proposals**, either:
@@ -63,7 +84,7 @@ The Gitlab will be kept up to date with your proposals, also translated into Fre
 _(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/n3
 
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