1. First Pink Coin

Move forward past the Buzzy Beetle. Once you see a pipe, under a wall, make a wall jump to get the first Pink Coin that’s on top of a row of bricks, with also a pair of Gold Coins.
2. Second Pink Coin

As you continue running forward and through the first pipe, you will find another platform with a row of Gold Coins. Among those Gold Coins is the second Pink Coin.
3. Third Pink Coin

After going through another pipe, Mario will drop to a lower level of the stage and find some more Buzzy Beetles running about. Then you will find another platform with a couple of row of Gold Coins sitting on top of it. The third Pink Coin is among these Gold Coins.
4. Fourth Pink Coin

As Mario moves forward, he will find another platform with Gold Coins on top of it. The fourth Pink Coin is included in one of those coins. Below this row of coins are a row of Munchers (black Piranha-looking plants) and another row of back dash buttons too.
5. Fifth Pink Coin

To get the fifth Pink Coin, continue moving forward. Once you see a platform of bricks with a Yellow switch on it, hop on that platform, hit the switch and make a high jump quickly after in order to get the last Pink Coin.