You have to build up your home and the land around it to help you survive the perils of the night. But there are tons of other people (myself included) who like to play in the more peaceful Creative mode and just focus on building. Not every game can parrot the success of Minecraft...
but if you have a friend who's already set up one of their own, you'll be able to join them as well. it's also worth noting that you can only join in-progress games if the world is set to survival mode, not creative mode. how to invite your friends to join your party in lego...