You just got your Nintendo 3DS, so I understand why you wouldn't want to toy around with taking it apart. We'll leave that up to the people at Pimp My Console. They put together this video so you can see how the 3DS can be disassembled.
The video is a bit slow so I'll tell you where to jump ahead to see the good parts. At 2:25 you'll finally see the backplate removed, showing all the innards. It looks like the accelerometer is being taken apart at 3:55. Right at 6:00 the mainboard comes away from the bottom screen. At 7:17 you'll see the surgery required to pop open the top screen assembly. Glue! Finally, at 10:41 the top screen comes apart.