Much of the ground is moving in this stage, but tapping will make it freeze for a moment. If you want the stamp, you'll need to play as Mario.
Before the checkpoint
Ahead from where you start is a block formation with a ? block. An invisible block directly above it holds a bell, so grab that and head right past the first rolling hill. Up the cliff behind you is the first green star of the level, and towards the camera is a M-Switch: Make Mario press it to acquire the stamp.
To the right is another bell power-up and a valley full of rolling blocks. Look under the lower-rightmost one for a 1-up, and get all the red rings for another bell. Up the big hill is the stage's checkpoint.
After the checkpoint
The boxes to the right of the checkpoint hold microgoombas, so don't break them unless you want a fight! Go forward and past the mice to reach a pipe to the second half of the level.
Underground, the path splits into an upper and lower section. The upper section holds a power-up, and at the end you can climb the wall for more coins. Down below, a green pipe will take you to the second green star. After grabbing it, there's a series of platforms, but if you drop below them you'll find a hidden area with the third green star. Take the pipes out of the cave to finish the level.