To find the Fireworks Artist, Basa, in The Legend of Zelda: Echoes of Wisdom, follow these steps:

1. Complete the Rift on Eldin Volcano Main Quest: This is a prerequisite to start the side quest. Make sure you have finished this main quest before proceeding.

2. Return to Goron City: After completing the main quest, head back to Goron City. This city is one of the main hubs in the game.

3. Locate Basa’s Workshop: In Goron City, go up the stairs and enter the room on the right from Darston’s room. This is where you’ll find Basa’s workshop.

4. Speak to Basa: Inside the workshop, speak to Basa. He will inform you that he needs more materials to create new fireworks for the upcoming celebration.

5. Find Blastpowder Soil:
– Fast Travel to Rock-Roast Quarry: If you have unlocked the Waypoint stone during “The Rift on Eldin Volcano” main quest, you can fast travel to Rock-Roast Quarry. If not, head northwest from Goron City to reach it.
– Locate Golden Flowers: Near the Rock-Roast Quarry entrance, look to the left and find a small hot spring surrounded by golden flowers.
– Collect Blastpowder Soil: Interact with the sparkling area next to the hot spring to gather the blastpowder soil.

6. Return to Basa with Blastpowder Soil: Once you have the blastpowder soil, return to Basa in his workshop and give it to him. He will be thrilled and inspired, and you will receive 50 rupees as a reward.

7. Learn the Firework Echo: After giving Basa the blastpowder soil, you can learn the Firework Echo. This echo is essential for completing other side quests, such as “Explosions Galore!” with Dampe.

By following these steps, you will find and assist Basa, the Fireworks Artist, in Goron City, which is crucial for progressing in the game and unlocking additional content.