Just talk to NPC at the registration office of the Sand Walrus Rally in the ruins on the right side of Grudd Town.

The Sand Walrus Rally is a small game in The Legend of Zelda: The Breath of the Wilderness. The participation fee is 20 rupees. The Legend of Zelda: Breath of the Wilderness is an open-world action adventure game jointly developed by Nintendo's planning and production headquarters and its subsidiary MonolithSoft, which was released by Nintendo on March 3, 20 17. This work is the main work of the legend of zelda series 15.