Start off by running straight ahead to the ? Block to obtain a Super Bell and receive the Cat Suit. If you haven’t played this before, this is the debut of the Cat Suit and it’s quite a powerful power-up for the crew, as it allows you to climb up walls and swat at enemies. Also, whenever you are in the air with the Cat Suit, you can press and hold X/Y to perform a diving attack, but you need to be careful with this. Run to the right and collect the coins, defeating the Goombas as you go. Head along the near side where the sand is located to find a hidden coin block and also start a chain of coins.
Back up top, you can jump into the clear pipe and hold up to claim Green Star #1. Continue to the right and into the second clear pipe which drops you off at the halfway point. From here, you can visit the Sprixie with binoculars to get a look at what’s ahead. You should find one of these Sprixies on every normal course, although they aren’t really needed, since the levels tend to be on the shorter side. At the top of the one bell tree, you will find a Super Bell out in the open, in case you need an extra one. There is a small pond nearby, where you’ll see a rabbit, which will take off whenever you get close. Chase after the Rabbit and catch it to obtain Green Star #2.
Head into the pipe against the wall, where you’ll see the Stamp atop the pipe. Enter the pipe to get on top of it and grab the Stamp, then exit via the green pipe in the corner. Back outside, climb the large back wall to the top where you’ll find a Rabbit and Mega Rabbit. Catch the Mega Rabbit to release a Mega Mushroom and snag the clock to add some time. Use the Mega Mushroom and drop off the ledge heading right over the bridge demolishing everything in your path. Your goal is to reach the blocks after the bridge that you’ll break. Drop down the hole to find Green Star #3, then use the Warp Box to go back out.
From here, head to the end of the level where you can start a coin chain. With the Cat Power-Up you dont have to cap the flag, because you will climb up towards the top but only so far. To truly 100% the game, you will need to hit the top of the flagpole, causing the flag to turn gold in color; this will also net you 10,000 points.