First Steps When You Arrive in a New Zone
When you arrive in a new zone in Pokémon Pokopia, the first thing you should do is build a small house and make it your home. Above all, because this is how you unlock the game's fast travel system: as soon as you place a Ditto flag on a house, you claim it as yours and can teleport to it whenever you want. This is very useful when moving between zones—something you'll do often—without having to spend too much time searching for the specific access point from the biome you're in.
House Requirements
Any house will work. You can buy house kits at the PCs in any Pokémon Center.
Construction, however, will require certain materials and a Pokémon with the building ability.
Tip: Place a Ditto flag on your house as soon as it's built to claim it and unlock fast travel to that zone. You'll save a lot of time when moving between biomes!