And, in addition to all the above posts, I have found that the "bible" for most everything Casita is the "CASITA TRAVEL TRAILER A-Z OWNER'S GUIDE
You can find it here
or at Amazon
I bought my Casita last year and I have found that most everything I need to know is referenced in the guide. If I need more detail, then I dive into FiberglassRV.com, CasitaClub.com, CasitaForum.com, or just plain old google.
One more reference: I'm a bit of a tweaker and I found several GREAT mods at Don Dayton's web site
complete with step-by-step photos with comments.