To access the battery you must remove the back cover. Press the tab on the bottom of the cover in so that the back cover plate can slide over it.
Now slide the back cover off of the phone.
Once the backplate is removed, look to the bottom-left corner of the phone where there is a spot to remove the battery.
Use your finger to lift the battery out.
Remove the four screws securing the front cover to the rest of the phone using a T7 screwdriver.
After the screws have been removed, there is nothing else securing the front cover to the rest of the phone. Simply remove the cover by pulling it up and off.
Once the front cover has been removed, there is nothing holding the keyboard to the rest of the phone. Simply remove the keyboard from the cover by lifting the keyboard from its interior side.