At the beginning of the stage, you should see a new power-up right in front of you, the Double Cherry. First introduced in 3D World, collecting one will create a duplicate of your character, while also retaining any other power-up they currently have. All of the clones will follow the same movements you input, so there is no requirement to do anything special to control them. Also, Double Cherries are never progressive, as you will always get one at their spawn points. If you get hit, then a clone will simply disappear into thin air. For the importance of this stage, though, you do not want to get hit at all. Lastly, you can only have up to five clones out at once; if another cherry was supposed to appear, it will be replaced by a coin.
Back to the stage, collect the Double Cherry in front of you, then make your way past the Galoombas and into the next area. Note that there is an invisible ?-Block in the left corner of the first area that contains a power-up. Break the boxes on the left side of the pipe for another Double Cherry, then the boxes on the right for Green Star #1. If you need it, the bottom block has another power-up, but otherwise use the nearby pipe. When you drop down into the new area, some Blocksteppers will be ahead of you. They simply ignore you and march back and forth on their predetermined path, but defeat even a single one and they will eventually come after you.
Get rid of the Blocksteppers, if you want, then just past them will be two sets of panels. You will need to split up the clones, so that you step on both panels at the same time. Doing this correctly will reveal Green Star #2. To the left of the clear pipes ahead is another invisible block, this one containing a Double Cherry; if you’ve been avoiding getting hit, you should have three clones in addition to your character now, so continue not getting hit. Enter the right clear pipe to get to the Checkpoint Flag. The next area is a series of slopes, occupied with more Blocksteppers, one of which is carrying another Double Cherry.
This next part can be tricky, but in the left corner of the area with the Blocksteppers is some ?-Blocks, one of which has another Double Cherry. You will need to get a clone on top of the blocks, as well as another below them. The left ?-Block will produce some more blocks that will be needed to raise the one clone into the air. At the top of the stack of blocks, you will find the level’s Stamp. Beyond the series of ramps will be a smaller set of ramps, with a Fire Bros hopping to and fro. Defeat that enemy to make a green pipe appear, so quickly enter the pipe to go to the final area.
The reason you want to be quick is because it’s quite easy to have your clones get separated from the main body. If they get too far from the main body, then they will actually disappear. You will want three extra clones before entering the final area, but if you don’t have them, then you can simply redo the stage. That’s because in the final area, there is a Multi-Vator, with the number “4” on it. As you might have guessed, you need four characters to stand on it in order for it to activate. If you’re playing four-player multiplayer, then this isn’t a problem, but if playing single-player, you need those clones. Should you have them, simply have all of them stand on it to rise up into the air and collect Green Star #3. From there, it’s a simple romp to the Goal Pole to finish the stage.