Once the two sides and the bottom are free, lift the bottom part of the cover slightly and push it up to release the headphone jack (yellow), and micro usb (blue) connections from the back cover.

The back cover should now come off leaving you with the insides of the Kindle Fire 7" (2015) exposed. You can see the battery (red), the main pcb (at top), rear facing camera (yellow), speaker (orange), and connection cables for the LCD panel (dark blue) and digitizer (light blue).