I'm spending my time on software at this point; but, opening up the back is easy so I took a few pics for you because I know how much it sucks to think about this thing with little info.
The first pic is sliding the back open. There is some doubles sided tape holding the back on so the first time is a bit of a pain. The back is meant to be able to come off so its a million times easier than other things I've opened like an iphone or xbox. Once you get the back opened like the picture of the outside, you can slide the back down and it comes of easily.EDITEDOnce you get the back off, you can see the mico sd card (see pic). The metal part that locks it in has text on it to show witch way to slide the metal mechanism:LOCK<--OPEN-->pull the old one out, put the new one in.I'm not 100% sure about the right way to format it.