*Note- You can obtain all three in one play through* [read guide below]
Once you get to the crater scene with all the lava and you have to reunite Yngo & Ralv. Once you fix the broken pray mill stone and move all the stones. Ralv will tell you a story. Really not hard to figure it out. The stone on the left represents life, middle is dream, and last one is death.
Riddle 1: move the blank [death] stone to the right
Riddle 2: move the moon [dream] stone to the right
Riddle 3 : move the blank [death] stone to the right
Riddle 4: move the sun [life] stone to the right
Riddle 5 : move the moon [dream] stone to the right
*Riddle 6* now this is were you pick which ever stone you want (life, dream, or death but in doing so will unlock that specific achievement. Once you pick one give it a couple of seconds. The achievement will unlock. Press start and reload to the last checkpoint if done correctly you will be at the very start rolling Ralv to Yngo. Repeat the process the other 2 achievements