Northwest of where you arrive in Hyrule, you will find a cave near the ruins of a ranch.

Cave Location

The southern entrance of the cave is located at 0038, -0201, 0020. It is northwest of where you land after you complete Nachoyah Shrine and jump from the Temple of Time.

Explore the Cave

A Horriblin guards the entrance of this cave. It will look down at you from the ceiling and throw boulders at you. Shoot it with arrows and try to hit its head to make it fall, then defeat it.

There is a small gap to the left that you can go through if you crouch. There you can gather Brightcaps, Brightbloom Seeds, and you will also find a Traveler's Bow and some arrows.

Crouch to go back through the gap, then go north to where you can see an opening in the cave wall. Use Ascend to reach the top of the wooden platform here, where you can find some Brightbloom Seeds, and a chest that contains a Traveler's Sword.

Go down to the ground, then before you go through that opening in the wall, go northeast to a tunnel opening. You will find a Bubbulfrog.

Then you can go back to that opening in the cave wall and go out from there.