I don't know about your particular model, but usually they're held in place by a few screws on either the top of the bottom and then have a few tabs on the opposite site that slide under a bezel or the palm rest. You should be able to just lift it up at an angle and "slide" it out after the screws are removed.
Edit: It'll probably be attached by a ribbon cable that you'll also need to disconnect before the keyboard can be removed entirely.
Edit: It'll probably be attached by a ribbon cable that you'll also need to disconnect before the keyboard can be removed entirely.