You better help that old man with the healing potion.
Talk to Adel about your situation. She will help you as soon as the library opens.
Unlike normal walkthroughs, in Nice Game Hints you can select just the puzzle you want hints for. Here are listed the puzzles for "Chapter 1 - Things get brewing" in Plot of the Druid. The guide you choose only contains information about that puzzle, reducing possible spoilers for other puzzles.