I am having difficulties with the puzzles, so I am going to restart the game and see if I've missed something in the caves, because I don't think I understand the first puzzle.
Heya! All the puzzle's clues are always within the same room/ area and for this particular one, the clue is located exactly on the object where you need to advance. I hope this helps :)
I see. I've discovered it. In the previous demo the hint was on the same object, but now I couldn't find it. I went there a couple of times and didn't notice the prompt at all.