It took us a little detective work but here is what I found worked - not sure if it's best but it worked.
1. There is a plastic cover piece located between the battery casing and front of car (grill). It is the piece with 4 screws and a lightbulb picture on it. Unscrew screws. It is a 2 piece plastic cover. We removed it as one piece but you might only have to remove one piece. To separate the pieces�twist slightly and move one piece up and the other down. 2. Unscrew the large bolt on the middle-front of the battery casing. 3. There is a small metal piece that holds the battery down. Remove it. 4. Remove battery. 5. When removing battery, keep in mind that the back of the battery is being held down by a plastic lip piece. You will need to remember to slide the new battery under that lip when installing it.
Also, snapping apart the plastic box that surrounds the battery was key for me.
(Facing the vehicle: two tabs on the left side, rear wall of the box and a round hinge-type snap at the bottom rear on both sides of the box, and on the left side the Positive Cable tie.) After that, sliding the battery forward with a slight tilt was all it took to remove the battery.