Left click on the symbol you see. When 4 symbols have been chosen, the correct one will glow.
Sometimes the answer can be guessed with only 3 symbols, because the entrance cannot be the exit ; the entrance can be marked by a right click on the symbol, but this weak aura is not yet capable of giving the answer early (to do, if the weak aura proves useful).
Reset by clicking the bomb.
I could not find the icons matching those in game, if someone does please leave a comment !
This video shows how to use the weak aura : https://youtu.be/Ka-Llwc3erw