Mini-World is a very fun sandbox game.
If you're playing Survival, you'll want to follow the concept of "get rich by chopping down trees", and no matter where you're born, you'll want to chop down trees, make a workbench, and then find coals to make a torch, and then build a simple house on your first day of life, so that you'll be able to get through the night in the safest way possible.
For other types of games, such as parkour and war mode, you can go to the online lobby and find your favorite type of game or build your own room to play.