Remove the four screws (blue). The screws are identical and interchangeable, so you don't need to keep track of which screw went where.

Release the two locking clips (yellow). The clips are holding the board down on the corners and it cannot be released easily without pulling back on them.

Take note of the speaker wires (red). They are soldered onto the board and special care should be taken to ensure they are not broken or otherwise disconnected.