The game's dev is notable for being somewhat of a troll when it comes to its achievements. For further proof, just look at the guides for Click on door 430 five times or Unachievable.
So as for this? This is very much a case of "exactly what it says on the tin."
Simply put, boot up the game once, close it, and then don't touch it again for five years.
If you're just trying to get the 'chieve for Steam and don't care about losing out on AStats points, you could just as easily set your computer's clock five years into the future and then boot up the game, but if the Mod note in the previous guide is anything to go by, this isn't an ideal method.