how can i do mission 8 the Nawawala woods?

Make sure the shadow is facing you, it will be a different direction you go in for all three, but as long as one of the shadows in each section of a particular arch is facing you then that is the specified direction you must go in. I know I'm right because the riddle says "Go towards the light" the only way you would know where light was coming from is if it was facing you and the only way to tell that is via shadows facing you. I hope I helped.