Hi Hagatha
I concur with oldman
The walktrough from gamespressure is really the best one
for this game. I played this game last summer (2014). And if I didn't have had summer vacation for 5-6 weeks, I'd probably be playing this game right now
Also, the games pressure game guide really helped me - a lot.
I can read German (since every Dane learn German in school) and I think I found one in German for this game at Gamestar.de - really helped a lot as well.