Get out of the closed area and follow the main road up to where the ticket station is. Jump up the blue containers and balance / swing to the Minifigure.
Back at race start, jump down and find the black/red glowing brick wall to the right. Smash it with Garmadon and run up the walls. Go to the far end and use Green Spinjitzu to put the parts together.
From here, jump down to where the big long red wall is. Run up that wall, climb up the wall on the other side and jump down towards the area, where the story started. Here, look around and notice the little blue roofs. Jump on those to get across and climb up to get the Gold Brick.
Now climb up to the car park, where you saved Cole in the story. There is a device at the car park level gates, where you can use Lightning Spinjitzu. Go up and jump over to the yellow car, where you can use Dual Swords . Switch to the other character to pick it up.