After filling the first Ewer in from the Wayshrine of Illumination in the Darkfall Passage, take the portal to Forgotten Vale. Go west and south up a corridor. Eventually it turns east and you reach a big chasm. Climb using the ramp on the top of the wall, and find yourself in a massive outdoors area, the Forgotten Vale. Head toward the marker on your radar. Check your map once in a while for orientation, it should show the locations of the four remaining shrines.
Note: All four remaining Wayshrines can be found in the Forgotten Vale.
You might need to carefully jump down from the cliffs onto the valley below. The first wayshrine should be around the northwest part of the Vale. Talk to Prelate Athring. He welcomes you the Wayshrine of Sight. Tell him you are prepared to honor the mantras of Auri-El and fill your vessel with his enlightenment. The Way shrine opens, fill the ewer from the basin inside.
Go southwest from the Shrine of Sight and up a path into the mountains. There will be several Frostbite Spiders on the way, including a tougher Giant Frostbite Spider. Turn southeast and swim a bit up the river and climb out. Near another gate, you see the second Forgotten Vale Wayshrine.
Talk to Prelate Celegriath, who welcomes you to the Wayshrine of Learning. Fill the ewer from the Basin in this shrine. Go northwest towards the waterfalls, and up the stairs on the side of the mountain. Climb the steep road uphill, then turn south and cross a stone bridge to the other side.
Talk to Prelate Nirilor at the Wayshrine of Resolution, and fill the fourth ewer. Cross back to the other side and descend into the stream of water. Go west on the stream (against the current), then south to arrive at some sort of Falmer Camp. Behind it, enter a Glacial Crevice. Go south in the Crevice, and climb the ridge on the side. There will be a Trip Wire on the way, so beware of the traps. You will also encounter Falmer Warmongers and Chaurus Reapers here.
Open a gate to the north, then go down, turn and cross a wooden bridge to the south. Keep descending through these bridges. Open another gate to the east, then keep climbing on north. Keep making your way through the tunnels, soon you locate the south exit from the crevice and exit back to the Forgotten Vale, but in a different area. You emerge in a narrow canyon, watch or the Falmers attacking from above.
Go through the Falmers' base and open a gate to the south. Enter a long, winding, tunnel that eventually turns west leading you to the last shrine. Tal to Prelate Edhelbor who is in charge of the Wayshrine of Radiance.
Once you draw the water from the basin in this final wayshrine, your objective will update to:
Gain Entry to the Inner Sanctum