Walkthrough: Mario and Cappy will arrive in Sand Kingdom in the town of Tosarena. This desert area has had a strange cold front lately, now having giant frozen icicles overgrowing the small town. Just past the town will be a shining pillar in the distance, the same coming from another tower in the ruins ahead, so start heading there as soon as you can.
As you make your way through the town, don't forget to talk to residents and visit the Crazy Cap Store. You won't be able to explore the entire town, as most of it is frozen over with numerous ice patches. However, you are able to find four easy-to-obtain Power Moons as you explore the entirety of the town. After doing so, head to the one side of the town and down the path that leads to straight to the ruins.