To obtain the Horse-Drawn Dreams in The Legend of Zelda: Tears of the Kingdom, speak with Zumi at the New Serenne Stable. She’ll need wheels to repair her busted wagon and a horse to pull it. To find the horses, head east.
When you spot some grazing, sneak up to one and mount it. Next, ride it back to Zumi. For the wheels, they can be found all around the stable. Bring the wheels to the wagon. Afterwards, the quest will complete and you’ll receive a Silver Rupee.