Instructions
Drive your cart into the first explosive, located to the right of the two-part wooden bridge that lies about halfway through the course. The explosive is directly to the right of the bridge on its own island. You can reach it by veering to the right and driving your cart off the edge of the road instead of following the bridge. If you keep up your speed, the momentum should carry you to the island.
Run into the second explosive, which is on the right side of the road right after the wooden bridge.
Destroy the third explosive, which is just a few feet past the second, on the right side of the road. This one is a bit harder to see and is easy to pass by because you come to it right after the road loops to the right.