Start by removing a single screw at the top-left on the back panel.
That's as far as I got.
A DDR3L SO-DIMM and possibly a battery are mounted on the other side of the circuit board but I didn't find a way of removing the circuit board from the case. I decided discretion was the better part of valour and gave in whilst I still had an intact and working C92.
In the photo below taken through the side of the C92 case you can see the top end of the line of contacts on SODIMM and above that parts of the label.