Secondly, if you see something green and depressed, run as far away as you can.
Fucking creepers. One of them blew up part of the stairway up to my hilltop base recently.
, there really is no goal for the game, so it's what you want to make of it. Personally, I'm a builder—I like to keep adding to my base, making it more and more elaborate and extensive. Others are miners and spelunkers, who enjoy going deep underground to find rare minerals. And still others just like to explore to see what the procedurally generated worlds come up with (the game can be quite stunning sometimes).
If you like, I can give you a good quick and dirty guide to surviving your first night, and where to progress from there...