I can't quite recall that model, but most Tv's you have to pull the speaker grill off to expose some screws along the bottom edge of the screen frame. Once the screws are out, either pull the entire assembly straight up an inch then out, or use small flathead screwdriver to pop the side edges straight out (start at the bottom) and once the side edges are loose lift assembly to release top edge out of groove.
Hammer
Hammer