Step 1 - Loosen (do not remove) the outlined bolt on the NEGATIVE terminal. Wiggle the wire and the bracket until it comes out.
Step 2 - Remove the POSTIVE terminal cap (yes the red cap with the "+" on it). Underneath it should look exactly like the negative side.
Step 3 - Loosening the similar bolt in Step 1 but on the positive terminal side and wiggle the wire until the bracket comes off.
Step 4 - Remove the black plastic piece because underneath that plastic strip is a nut you need to loosen to get the battery out. For the push screws, use a pen or screwdriver and lightly push the middle pin in and the screw should pop out. Take the screws out and pull the pin all the way out (will help you re-insert later)
Step 5 - Remove the bolt that is holding the metal piece that is across the top of the battery. Watch out not to dislodge the metal hook at the back. If you do, just re-hook it when installing the metal pice back.
Step 6 - Remove the bolt on the OTHER end of that metal strip. Remember you removed the black plastic piece? This is why. This screw is under it.
Now just pick up the battery and swap in the new one and then reverse what you just did. When putting the screws back in to hold the black plastic piece, you want to insert the screw first and then put the pin back in. When you push in the pin, it should be flushed to the screw.
Sorry Carbon I jacked your picture and drew all over it. I used MS Paint because I was too lazy to start up my other computer and use Photoshop.