I was wondering myself. I had to open this piece up because the power supply did not work properly and I need to change the exterior casing and power supply circuit. I tried to look for any manual or instruction to open it up but to no avail.
So I gave it a try. And to help others, this is the way to do it.
And gonna make it simple and straight forward. All you need is a flathead screwdriver (or something similar).
Step 1: Unscrew the Casing
Unscrew this first.
Step 2: Side Panel
You can see from the picture where you need to pry it open.
Once the side panel is off, you are pretty much halfway there.
Step 3: Other Side...
Pry them open with a screwdriver as well.
Step 4: Front Side
After that you can just pull the indicator LED upwards.
Step 5: ...and the Rest...