Hallo Joseph,
Thank you a lot for answering - I'm really sorry about not being clear 
Thank you for your solution too but it would mean I have to explain every time (in 4 languages) that they have to click on the category tab first, and they have to read that and to do one bothering click which they might just not do...
Maybe I should I start my question another way:
I suppose that the FAQ on moodle.org (the image I put) is done with the glossary FAQ module.
- If yes, how did they do their summary/table of contents (what you see on the picture) ?
- If no, what tool have they used ?
I hope that is clearer...
Ulrike
PS: I join an image to see what the first page of my FAQ looks like