Hi, Ene,
You are very, very fast as explorer!! Congratulations! But perhaps too fast...
"I suppose I need to drop a power gem here, right?": ............................................................... Yes, but you see, you have four pedestals, so...
"What are the green drapes for? Do they trigger something (by touching them?)": ............................ some of them are only for decoration (but give a glance to the motives), some can move.
"A clue here please

(is it relative to the '5up, 4down, 1down' scroll)": ...................................... Yes! Feel free to try different solutions and think to reinitialize if you want to use the scroll.
"How do I deactivate these magic walls - there are few of them.. ": ...................for now, my better answer is : have you killed some wizard near by? If yes, search his papers. And give a look to the missions page in the Magic Book (click on the tree seal)
................................................................................................................................ I see that you have found the drawned god, now, rescue him !
Also, I found 2 meteorites, should I keep them?": ................................................................... they are very heavy, but useful... put them in some place, you can get them back later.
The walkthrough gives mainly directions, not complete solutions, sorry.