I've updated the first message to contain more info about the puzzles:
When you are solving the puzzles and following the clue, asterisk (*) symbol marks an extra element. If you use it - the spell will become too strong for the current level. To solve the puzzle you need to remove the element marked by the asterisk.
Once you have the correct combination of the elements (everything on the clue but without the asterisk element) - rotate them into a correct position.
How would you know if it's correct? They will start to glow.
How would you know if the puzzle is solved before actually casting the spell? You'll see glowing runes appear around the centerpiece.
In later levels the scroll with the clues is being hidden underneath the puzzle area, you'll see the edge of the scroll sticking out. Click on it.
There are three groups of the elements:
Corpora Caelestia - circles, triangles and squares
Elementa Alchemica - pentagons (5 sides), hexagons (6 sides), octagons (8 sides)
Potentiae Ocultae - heptagons (7 sides)
The ranking goes - Potentiae ocultae > Elementa alchemica > Corpora Caelestia. Which means Heptagons rotate themselves and everything else, Pentagons rotate themselves and the Circles, Hexagons rotate themselves and Triangles, Octagons rotate themselves and the Squares.
So you should first rotate Heptagons (when present) into a position, then penta-hexa-octa, and the simpler elements like circles, triangles and squares should be last.
If you cast the wrong (or too advanced) spell too much - you'll deplete magic and would have to wait a day or two until it recovers. In the future there will be mana potions but not in the current version.