In the courtyard ahead, we can see previous phantoms by interacting with Black Soul.
Follow the phantom and approach the door ahead. Our prosthetic hand will glow blue. At this point, press V to activate "Eye Awakening," which reveals hidden objects.
Use Eye Awakening, turn around, and strike the small spider. Once the spider is defeated, the door ahead will open.
There are many Phantom Demons in the courtyard ahead; eliminate them. Enemies with their backs to us can be assassinated directly.
A new system called "Clash of Blades" appears during combat. When locked in a standoff with an enemy (indicated by a close-up clash animation), you can switch attack methods to deal damage. Simply put, if a Clash of Blades is triggered by a left-click attack, counter with R; if triggered by R, counter with left-click.
Continue forward and deal with the enemies in the courtyard. Don't go left for now; keep going straight.

