How to Find Hyetta and Complete Her Quest

First Meeting - Lake-Facing Cliffs: Head to the Lake-Facing Cliffs Site of Grace in Liurnia. After refreshing the area, you'll find Hyetta. If you have a Shabriri Grape (found north of Godrick the Grafted Site of Grace in Stormveil Castle), give it to her. She will teach you the 'As You Wish' Gesture. Rest at the Site of Grace, and she will move on.

Second Meeting - Purified Ruins: Travel northeast in Liurnia to the Liurnia Highway South Site of Grace, then head northwest to the Purified Ruins. Find Hyetta on the west side. To get the second Shabriri Grape, head northeast to another part of the ruins, defeat the soldiers, break the planks on the ground to reveal stairs, and collect the grape and the Two Fingers Heirloom. Return to Hyetta, give her the grape, and exhaust her dialogue. Rest at the Site of Grace, and she will move again.

Third Meeting - Gate Town Bridge: Activate the Gate Town Bridge Site of Grace in eastern Liurnia. Then, head to western Liurnia, north of the Minor Erdtree, to find the Revenger's Shack Site of Grace. Rest, enter the shack, and defeat Edgar the Revenger to obtain the third Shabriri Grape. Return to the Gate Town Bridge Site of Grace; Hyetta will be north of it. Give her the grape and tell her what they are. After she reacts, rest and speak with her again, then rest once more. She will move to her next location.

Fourth Meeting - Bellum Church: Travel north along eastern Liurnia to the Ruined Labyrinth Site of Grace. Head northwest, drop down using tombstones to the land below, and proceed northwest to Bellum Church. Hyetta will be there requesting a Fingerprint Grape. To find it, head northeast from Bellum Church, then southeast towards the Grand Lift of Dectus. Climb up to the Frenzied Flame Village. Go to the tower on the left, defeat the Maniacs, then head northwest to the Church of Inhibition. Be prepared for an invasion by Festering Fingerprint Vyke; defeat him to obtain the Fingerprint Grape. Return to Hyetta and give her the grape. She will decide to become a Finger Maiden. Rest at the Site of Grace. She will then move to Leyndell.

Fifth Meeting - Frenzied Flame Proscription: Progress to the Subterranean Shungeons in Leyndell, Royal Capital. After defeating Mohg, the Omen, strike the wall behind the altar to find a hidden path leading to the Frenzied Flame Proscription. Speak with Hyetta here; she will hint at how to open the door ahead by removing all equipment, granting access to the Three Fingers.