Update textbook.es.md

00.brainstorming-pedagogical-teams/03.presentar_el_proyecto/textbook.es.md

@@ -16,7 +16,7 @@ https://m3p2.com/es/m3p2_pedagogy/m3p2_structure/overview
 
 https://m3p2.com/polyglot-columns/m3p2-pedagogy/pedagogy/summary
 
-Por ejemplo 
+#### Por ejemplo, para los estudiantes
 
 * parte principale
 
@@ -34,7 +34,14 @@ https://m3p2.com/en/m3p2-curriculum/physics-chemistry-biology/niv3/Geometrical-o
 
 http://localhost:8000/en/m3p2-curriculum/physics-chemistry-biology/niv3/electromagnetism
 
-Para los profesores, la estructura de un curso
+
+##### Para los profesores, la estructura de un curso :
+
+https://m3p2.ljbac.com/m3p2/courses/tree/master/01.curriculum/01.physics-chemistry-biology/03.Niv3/02.Geometrical-optics/05.paraxial-optics/02.paraxial-optics-simple-elements/03.lens
+
+https://m3p2.ljbac.com/m3p2/courses/tree/master/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/02.new-course-overview
+
+https://m3p2.ljbac.com/m3p2/courses/blob/master/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/03.lens/02.new-course-overview/cheatsheet.en.md