In case there is any adventurer who at some point has been lost, I leave here the series of 6 official walkthroughs of the game found on Youtube:

Part I - The druidic grove.
https://www.youtube.com/watch?v=xsUi6PXe5Tk

Part II - Skye sneaks into the city.
https://www.youtube.com/watch?v=M2SbkiIx528

Part III - Skye meets Percival and the witch
https://www.youtube.com/watch?v=_FPLnYh6Ji8

Part IV - King Finn's castle
https://www.youtube.com/watch?v=_yE9NCHor6c

Part V - The three ingredients.
https://www.youtube.com/watch?v=0E5Z1munzPc

Part VI - The tower of Malgrim.
https://www.youtube.com/watch?v=rFMar7XRmBQ

They do not show the achievements.