Best way to set up co-op in Stardew Valley with a friend?

every extra player needs a cabin. either tick the starting cabins option when you make a new farm, or buy them from Robin on an existing save. then load the save, hit Co-op, and host. your friend joins from the Co-op menu on their end - through steam friends, or with the invite code if you're on different stores. couple of things to know before you start: it's always the host's save, so they can't play that farm without you. and money is shared by default. if you'd rather each have your own, you can switch that at the ledger in Lewis's house. split screen works too if you're on the same machine.