You can park in any of the garages that are open. Lime is my favorite, because it's closest to Marketplace, but they tend to leave it closed until later in the day (or when the Orange garage gets full maybe?) and since we rarely go late at night, we end up in Orange a lot. We've never needed to park in a garage other than Lime or Orange. Both of these have direct access to Disney Springs on the 2nd level (park on 2 if you can!).
The signage on the street is super easy to follow - it'll tell you if the garage is open or not. Inside the garage is super easy to navigate, too, with lights over top to show you which spots are empty and each row displays how many spots are open on that particular row.