Discover the Illusionary Wall:

Descend further using the ladder ahead. Follow the path until you reach a room with the "Domain of Elden Ring Items Dragons" painting.
On the southwestern wall of this room, locate two torches with an apparently ordinary wall between them.
Hit the space between the two torches to reveal an illusionary wall.
Reach Castle Watering Hole Site of Grace:

Follow the path beyond the illusionary wall to find a stone coffin. Interact with it to reach the Castle Watering Hole Site of Grace.
Navigate Southeast to Recluses' River Upstream Site of Grace:

From Castle Watering Hole, head southeast along the rockface to reach the Recluses' River Upstream Site of Grace.
Continue following the path, jumping over gaps until you can cross over to the path on your right.
Find Recluses' River Downstream Site of Grace:

Progress along the path until you reach the Recluses' River Downstream Site of Grace.
Look over the eastern edge of the cliff to best site to buy elden ring items find gravestones that lead down to the bottom of the waterfall.