Stomp the Koopa just past the Gold Ring, then carry its shell to Point 1. Toss the shell onto the pink platform, then follow it as it speeds through the nearby enemies. As you do, each platform reacts to your presence.
If you stay too close to the shell, the blue platforms drop out of position. If you stay too far from the shell, the pink platforms will fail to move into position. If you time it just right, however, the shell will hit the Block just past the platforms to reveal a 1-Up Mushroom.
The first Star Coin is floating between the platforms at Point 2. To collect it, stomp the Koopa patrolling the platform to the right, then throw its shell at the Star Coin.
The second Star Coin is located in a hidden area. To find it, hop onto the pink platform at Point 3, and stay put until it carries you off the screen.
When the pink platform stops, the Star Coin appears to the right. Jump over to grab the Star Coin, then use the green pipe to leave the area.
Before you pass through the Red Ring at Point 4, clear out the Koopa Paratroopa that’s patrolling the area. After you trigger the Red Ring, move between the pink platform and the two blue platforms to grab each red coin as it drifts down from above you.
The third Star Coin is located below the blue platforms at Point 5. As the patrolling Koopa moves into position, drop down to grab the Star Coin, then stomp the unsuspecting enemy and bounce back up to the platforms.