To remove the battery, loosen the 9 screws on the laptop base cover. Pry the cover away from the recess points near the hinges. Lift the cover up and away from the system. Identify and unplug the battery cable. Find the battery and loosen the 5 screws securing it to the system. Lift the battery up, flip it over. And disconnect the cables.
To reinstall the battery, reconnect the cables. Flip the battery over and place it back in the system. Secure it to the system with the 5 screws and connect cable. Place the base cover back on the system and secure it with the 9 screws.