Monk #1: Chapter 1 - The first monk is along the main path. Climb the steps up to the tall statue with three square stone runes. He's sitting to the right.
Monk #2: Chapter 1 - Backtrack past the deer and go up the wooden stairs to use the telescope. Enter the tower and check the dead end to the right of the interior.
Monk #3: Chapter 5 - In the tower, Moonchild sneaks behind pillars while a creature watches from the background. Continue to the final pillar and attempt to pass the sitting monk to enter this dream.
Monk #4: Chapter 9 - Very close to the starting point of the chapter. It's right at the beginning.
Monk #5: Chapter 10 - As the chapter begins, head down the path straight ahead, up the stairs, across the bridge and complete the required steps until Moonchild backtracks to the tower. The monk is sitting on the exterior of the tower when you return.