Hi Marc
As the manual says
'Inside the all yellow section you will find 3 other sections, slide out sections No. 5, 6, 8
Make sure you pull these from the slightly larger bottom end. The number 8 section may need pushing out from the opposite end.'
To push the No 8 out from the opposite end (smaller end) you may need something to push with. I would use something like the blunt end of a wooden pencil.