Start at the Grand Lift of Dectus or the Forbidden Lands, depending on your progress
From Altus Plateau, head northeast toward the Capital Outskirts
Follow the main road into Leyndell, Royal Capital
Continue through Leyndell until you reach the avenue leading to the Forbidden Lands
Leave Leyndell through the eastern exit to enter the Forbidden Lands
Follow the road east through the snow-covered area
Reach the large bridge and continue past the enemies on the path
Follow the route to the Grand Lift of Rold
Use the lift to access the Mountaintops of the Giants
If you have not unlocked Leyndell, first defeat the required shardbearers and use the Dectus Medallion or the Ruin-Strewn Precipice route to reach Altus Plateau