This page explains how to start and complete the Tools of the Trade side quest.
How to Start the Quest
To start this quest, you first need to reach Gerudo Town. Then talk to Isha, who is standing near the northeast entrance of town, to start the quest.
How to Complete the Quest
To complete the quest, you need to give Isha 10 Flint. Flint can be found in Ore Deposits, which can be found on rocks, especially on cliff walls and mountains.
After you give her the Flint, she will offer to make one free accessory for you.