Hi, i'm a minecrafter (player).
So basically it depends on how you play the game.
There are three modes; survival, creative, hardcore.
Basically the main goal is complete all the achievements and survive. You start with nothing, no instructions and learn from there/look for "recipes" on how to make things.
Example: Punch a Tree to get a wood block, craft 1 wood blocks into 4 planks, you can then craft 4 planks into a crafting table. This gives you a 3x3 crafting grid instead of the 2x2 one that's built into your character. 2 planks on top of each other crafts into sticks. One stick with 2 planks with on top of it gives you a sword.
If it sounds confusing, well it really isn't just takes a bit to get use to.
That's basically survival mode, Hardcore mode is survival mode but you only have 1 life.
Creative mode allows you to build stuff. The whole world is basically a sand box styled came, go where you want, do what you want, build what you want.