1. Go to Braavos' tavern, talk to Gorbo, he will tell you come back later to receive a job.
2. Tab out, go in the tavern again, now there will be a playwright Phario Forel, talk to him. He needs Andal tressures for his new play, pointing you to an Old Barrow near Ruins of Iksa Calo.
3. Visit the Old Barrow (it's actually closer to the village Upper Rhoyne). Walk down the stairs to the second open iron gate, you will interrupt five cultists and have to easily kill them to receive a handful of supplies (hides, some foods, etc). about 15 items, 70% food.
4. Go back to Phario Forel to tell him that you didn't find any Andal treasures, receiving 500 exp and keeping the Nasal Helm.