Pull the side dash covers off, then the a-pillar trim. Both are held in place by clips. Then pull the top dash trim off. You will see the speaker. I found it easier to disconnect the wires after unbolting it. I used a ratchet with a phillips head bit in a 1/4"socket since there isn't a lot of clearance between the windshield and dash. Installation is the reverse.
I do agree with others that you will not notice much difference if you just leave it out. If you already have the replacement you might as well change it but if not just disconnect it and see how you like the sound. Remember, if you blew the original one you'll probably blow the replacement sooner or later.