What Is The Main Goal In Minecraft?

To just build.
There's no central goal.

You just survive. You get to build what you want, craft as you see fit, or go mining. The concept is a little daunting at first but just start by gathering wood and building a simple house

There's no main goal. Lol. Just 'mine' and 'craft'. Simple. The world is yours to explore in the game. Just make sure you build yourself a nice house before nightfall in Survival Mode. Don't need any creatures bothering you. Especially creepers… Nasty!