NOICE! Congratz, JB!
1st task was:
DREMEL /cutting those little edges, otherwise the roof wouldn't sink into a proper position
It was even more, than the photos show. The paint shop fixed the holes in the fiberglas later on.
2nd task was:
carefully drilling the screw-holes open. I noticed, that all the screws would only go like half way in, and the seller gave me the advice to drill them open and NOT to use force screwing them in/through.