At the top. Take out the four screws, take an opening tool, crack it and slide the tool down the sides. Easy to open, easy to swap the SSDs. That was the easy part. Disputing the charge because the 3G doesn’t work, this is a pain.. Honestly, the hardest part about opening it is closing it back up, the power/volume switches. Comes as one piece but inevitable separates. Then getting them back in and together.. That is the biggest pain in opening/closing this device.