On the Wii U version of the game, you will be using the Gamepad extensively in this level. However, in the Switch version, you can either use the touchscreen in handheld mode, or the cursor that appears whenever you press L or R. This is a Japanese themed level, which has a lot of sliding doors, with those requiring the above to open them. At the beginning of the level, touch the sliding door and jump into the pipe. Defeat the Goombas and hit the ?-Block at the end of the path to find a power-up (Boomerang Flower). Move the sliding doors and walk behind the wall, around to a Goomba, under the stairs, that guards a Super Mushroom in an invisible ?-Block.
Return and head up the steps, only to have them turn into a “slide” and trigger a Spike to toss spiked rollers at you. Quickly ascend and take this guy out. then check the back wall on the left side to reveal another hidden ?-Block that has a power-up. Continue left, ignoring the first door (only has coins behind it) and opening the second set of sliding doors. Behind them will be two P-Switches, with the right one revealing another hidden section that has two Goombas. Defeating these Goombas will have them leave behind a Goomba Mask.
Putting one of these on will not only make it so Goombas/Galoombas ignore you, but it will prevent you from using any power-ups. Hit the other P-Switch to cause some stairs to come down, then head up them and hit the gong to cause some coins to fall. As you continue right, open the doors to a seemingly empty room, but stepping into the room will make the walls open up, revealing Green Star #1. You can grab a clock pick-up further right, with a Coin Coffer hiding to the right of the clock. Open the doors at the end of the hall to find a Warp Box to the next area.
Touch the Checkpoint Flag, then get to work collecting the five Key Coins in this area. Before doing that, though, cross over to the right side to find a bunch of ?-Blocks, which are Propeller Boxes. Don one of them, then jump into the pit into the middle to grab Green Star #2, before flying back up to safety. Key Coin #1 will be in a small alcove behind the two Thwomps on the second level. Key Coin #2 will be on the clouds right behind the first one. From the second one, journey a little to the left and jump to the next tier, where you will find Key Coin #3 floating above a pit. Continue to the right and grab Key Coin #4 on the cloud, then jump up to the final tier, with Key Coin #5 right there.
This will unlock the Warp Box, but make sure you have a Propeller Box before moving to the next area. Ignore the gongs here, as the first summons Goombas and the second just drops some coins. When you get to the Spikes, you can head towards where the rollers go to appear back outside. If you still have a Propeller Box, fly on top of the rooftops here to find a cloud platform, which will be housing the Stamp. Return inside with the Spikes and continue all the way right, ignore the Warp Box at the end. There will be another gong past it and if you hit it, then a Mystery Box appears. Defeat the Spike inside to get Green Star #3. The Warp Box in the main area will take you to the Goal Pole area.