Before prying up on the cover, you may have to first remove a screw located inside the battery compartment (M2X3) and release the two latches. If you don't release the latches, you may snap the cover.
Pry up the top of the cover first by using a spudger to wedge in between the cover and base of the computer.
Once the spudger is between the cover and the base of the computer, wedge underneath the remaining border surrounding the keyboard.
Cracking sounds are normal. Be careful and take your time removing this panel.
Work your fingers underneath the cover. Then, delicately pull the cover off of the computer.
The mouse pad is connected to the rest of the computer via two cables underneath the cover. These cables must be unhooked before the cover can be completely removed.