How do i unlock the upper left side of the Snow biome?

[DaMaster337]

i already beat the elden beast and i am about to start journey 2 but i still havent unlocked the left side of the snow biome. i think thats the location i need to beat malenia and i still have not beaten that boss yet and i already beat the elden beast.

[CazadorDeLobo]

Secret Haligtree Medallion needs to be used - 'Switch Action' at the Rold lift