|Pyro as Bill said:
I think I played FE on DS.
Is it a medievally version of Advance Wars? Archers instead of artillery n shit?
For someone who couldn't care less about story or micromanaging is there anything I should/shouldn't do to ensure I'm not wasting time?
If you do decide to get it, you'll want to play in casual mode, not classic. This avoids permadeath, which gives you more room for error so you don't have to micromanage as much. There is a lot of time spent outside of battle, and that might be boring for you, but most of it is skippable. Just understand that doing so makes the game a lot shorter. Of course, since you can play it more than once for up to four endings (1 for each house, plus an extra ending under the Black Eagles house), you might still be able to get plenty of hours out of the game. By fast traveling and only doing what's absolutely necessary with Explore mode, you'll save a lot of time with the story. Of course, a lot of the appeal of the game is building up your characters, so you might not get much out of it if you play that way. But you certainly could play that way if that's your thing. The time spent on the micromanaging and character building does have a tangible effect though, so if you go this route, stay away from the tougher difficulty levels, which would be balanced around you taking advantage of every opportunity for growth.