Thank you Alex for you quick answer.
A/ If I want Replace the block 1 by the block 2, How can I do ? ( Head "category", and under "Featured courses") like this my customer or clients will know which kind of different courses there is.
B/ If I want more than 5 Featured courses in the block 1 and 4, how can I do ?
C/ If I want change the theme ( textes color )
D/ how can I do for access to the first slide fo change the texte?