Update textbook.en.md

00.brainstorming-pedagogical-teams/45.synthesis-structuring/electromagnetism/n1/textbook.en.md

@@ -12,4 +12,17 @@ lessons:
 
 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 pedagi
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+This tree structure may evolve, but it is less agile than the educational content
+themselves. I
+
+n 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:
+What knowledge on this topic is useful in everyday life or for understanding future technologies?
+What worries them or scares them?
+What amazes and amazes them?
+
+Chapter titles should be words from everyday life. 
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