Kinda just whatever you want it to be. There's a basic 'intended route' or 'progression' but that's just there as a general direction to go in while you figure-out what you want the game to do. It's really open-ended and geared towards you being able to develop your own goals and ideas.

I, for example, really like collecting stuff. So, I gather stuff to survive and make a house with a 'display room' that works like a check-list while I collect every item in the game.

I also have a big cooperative world where my friends and I do city-planning and build structures around that.

There's also the most vibrant modding-scene I've ever seen in a game which adds tonnes of depth and a more 'goal-oriented' experience.

It just has a little bit of something for everyone. If you like fighting, there's the zombies, Dragon and Wither. If you like exploring, there's giant caverns, mineshafts and structures. If you like collecting, there's tonnes of hard-to-find items and blocks that only appear in special places. If you like building, there's a massive pallet of 'colours'. And if you like anything else, there's a mod to add it, everything from firearms and Rube Goldberg machines to Pokémon-hunting.

It's really popular because it's so accommodating and paced so that you keep bumping into things that inspire you to work with them. Add friends into the mix and you really start to spiral with creativity.

There's just something about Minecraft that feels enjoyably 'healthy'.

There are plenty of guides to using it for different things. I was able to get it setup with emulators when I was a teen, I'm sure you could find a comprehensive guide to step you through anything you'd like to do.