If you look through the grille, you'll see 4 screws at the top, and 4 at the bottom. Remove these and carefully slide out the grille forward. You'll probably see some remnants of white paper tape under the grille edges-- this is original (they installed it this way in order to prevent paint scratches).
Next, you'll need to remove the inner grille guards (black louvres). These are affixed using impossible-to-access screws on the top and bottom edges. You'll need a screw driver with a very very very short handle and little baby hands to do this. I'm sure others here can help with better instructions.
