Just like a fish .... Run a knife from anus to throat, pull everything out ... Flush abundantly with water, you can skin it if you want at which point you want to cut off all 4 feet then run an incision inside from the tip of the newly created stumps to your main incision, and rip the skin/furr off (it will come right off like a sock most times).
Its a lot like cleaning a rabbit, really.
ps: As of last year I had never cleaned anything but a fish, so I was quite nervous until I realised that the procedure is quite similar and you don't have to worry about much ....