Use the pulley platforms at Point 1 to reach the first Star Coin. Stand on the right platform to raise the left platform into position. Hop up to the left platform, then jump straight up to collect the Star Coin.
The second Star Coin is located in a secret area. To reach it you must reveal the Beanstalk hidden in the Block at Point 2. Stomp the Koopa patrolling the platforms above this area, then throw its shell at the Block.
Climb the Beanstalk to reach the secret area, then jump up along the platforms. The Star Coin is floating at the top of the area.
When you jump through the Red Ring at Point 3, the red coins appear around the nearby pulley platforms. You must adjust these platforms to collect all of the coins, so make sure you don’t break them! Any time wasted waiting for the platforms to reappear could prevent you from completing your task.
The third Star Coin is floating above the pulley platforms at Point 4. Use the lower set of pulley platforms to reach the upper set’s left platform.
Stand on the left platform until the right platform is as high as it can safely go, then use it to reach the Star Coin.