Minecraft is split into two separate game modes. Creative and Survival. If you want to make huge structures from scratch with unlimited resources, Creative mode is used. You wont see any enemies, and you can pull blocks of all shapes and sizes out of thin air. Its a peaceful world. However, if youd prefer to adventure into a world of danger, where youre crafting and creating out of necessity, play in Survival mode. That comes with gangs of monsters who want to break/explode/eat your bones, one pixel at a time. Youll need to protect yourself from the creatures that come out at night.