Starting at the top, gently raise the keyboard enough to remove it from the socket.
Potential for device damage: DO NOT pull out the keyboard after it's out of its socket. The keyboard is connected to the hard drive through a data cable and removing forcefully could damage the cable and laptop.
Use the iFixit opening tool to begin removing the cover.
After creating enough space, you can use your hands to completely open the cover.
Possible Device Damage: Make sure all the screws have been removed before attempting to open the cover, or else the screw threads might strip if too much force is applied.