The only thing you have to know before playing Outer Wilds is that knowing anything about the game will spoil it.

Will you like it ?
Well if you like games telling you what you have to do, where to go or stuff like that, maybe the game is not for you. Otherwise, if you are curious, like exploration and discovery, I strongly recommend you give it a try.

For me, this game is the best experience I had in a long time.