Lower level/ Pushing the first stone panel - After getting the Heath Position, turn to face the centre of the room and jump to the ledge below. Turn right and approach the left side of the ledge. This part is closer to the opposite walkway, so jump above the toxic water to grab the edge of the walkway and pull up. Turn right and enter the alcove with the glowing symbol.

Grab onto it and push the stone panel forward as much as you can.

The brief cut scene shows that this action reveals the power mechanism on the back of the tower above.

Walk back to the other side of the walkway and turn right (you are still going anticlockwise). Jump to the ledge below and jump to grab the next walkway.

Pull up and notice that the walkway is broken, so you cannot reach the stone panel.

Pushing the second stone panel - Continue anticlockwise, jumping down to the lower ledge. Then jump to grab the next walkway and pull up. Deal with the Yeti thralls that may attack and enter the alcove on the right.

Grab onto the glowing symbol and push the stone panel to reveal the second power mechanism.

Walk back to the other side of the walkway and turn right. Jump to the ledge below and jump to grab the next walkway. There isn't any panel on the right, however this is the way to get back to the middle level.

Climbing back to the middle level - Vault onto the low stone ledge and pick up the Health Potion. Enter the space between the two pillars and perform the Chimney Jump to grab the handhold on the left pillar.

Traverse to the right and jump to grab the next handhold. Press the down direction key and jump to the pillar behind. Keep tapping the Jump button to perform the Chimney Jump and grab the ledge above.

Alternatively, while hanging from the handhold, you can traverse around the pillar to reach the back of it and jump up twice to grab the topmost handhold. From there, jump to the left to grab the ledge.

Climb on the next ledge and...

... jump to grab the upper walkway. Pull up.