In Hyrule, after you get the Sand Rod (If you can't get the Sand Rod, finish the Thieve's Hideout, in Lorule's equivalent to Kakoriko Village), go south of Link's house as far as you can. Then, go left, avoid or defeat the blobs and buzz blobs, and go into the crack. In Lorule, go left again. After Hilda talks to you, find the nearest crack on the the pillar to the north and go in.