Walkthrough: When Mario hits the land below, he will actually be in what is known as Cap Kingdom instead of his home of Mushroom Kingdom. After hopping up and gaining control of Mario, you will notice you are in a town called Bonneton. A ghostly hat-shaped figure will appear and then run off, forcing you to give chase to him. This would be a good time to learn the most basics of Controls as you do. After chasing the figure all the way to the town gate, this ghostly inhabitant will introduce himself as Cappy, and he'll actually take the form of your restored trademark hat.
With Cappy as your newest companion, you will actually be able to use him to attack and perform specialized moves. While in the area full of homes and airships in disrepair, get the hang of using Cappy to his fullest potential. From the main gate, head to the right to find a lower platform. You will quickly come to an alcove, one with a wooden peg actually blocking a hidden area full of many Coins. There will also be loads of coins to the left of the main gate, directly behind the Bowser Wedding Posters.
Continuing exploring the area as you make your way to the far side, crossing the raised platforms as you do. If you need help destroying the wooden crates that stand before you, try having Cappy do the work for you. At the end of the road, you will actually come to a bridge. Toss Cappy at the lever in sight to cause the bridge to be lowered, the same that leads straight to Hat Tower. However, at the end of the bridge will be a number of yellow Goombas that will attack you. Jumping on them will do the trick, but they can also easily be defeated by batting them down with Cappy. After defeating all of them, hit the door to the tower for it to open, and then head inside.