Third Courtyard

Walkthrough: As you enter Bowser's Kingdom, you will need to make your way with Mario and Cappy from courtyard to courtyard in order to reach his Castle. You will begin with the third courtyard, the same that is broken up into several different platforms that you'll reach using the Spark Pylons found throughout. Each platform will have puzzles and secrets to solve, like the one directly behind the Odyssey Airship. This platform award you with a Power Moon by spinning on one of the Bowser railing ornaments.

Move through the large ornate doors ahead of the ship, and then head to the right to jump and climb the wall to find some Purple Coins. After obtaining them, head back to the main path, moving down the steps to find a wave of Goombas. If you stack ten Goombas and go around the bottom right corner of the area, you can find and reveal a pressure plate to obtain a Power Moon. After you do, take the Spark Pylon into the next area.

There will be helmeted birds known as Pokios here, the same that will try to attack using their beaks. Dodge them and knock of their hats in order to capture them with Cappy. After you do, move to the right to find a number of white walls. Use the capture Pokio to stab and stick into the walls, flicking yourself upward to reach the top of the walls. You will find the next Spark Pylon here, but before using it to reahc the next area, don't forget to grab more Purple Coins by descending down the rooftops, as well as a Power Moon by dropping down the other side of the white walls.

Use the Spark Pylon to reach the platform. There will be two Spinies on it when you do, so deal with them before obtaining the Power Moon by tagging the Musical Note on the left. After defeat the Spinies and obtaining the Power Moon, cross the platform to the battle the Gatekeeper, the Stairface Ogre. He will slowly move around, trying to keep you in front of him as long as possible. After a certain amount of time, he'll lock targets and his shadow will begin to turn red. He will swing his hammer down after this happens, so quickly dodge it to avoid taking damage. After he does take a swing, jump on his now exposed head. From there, vault his fallen hammer in order to do a ground-pound to defeat him. Once you do, you will awarded a Power Moon and be allowed to move forward.