[How do I cloak a building?]

I am trying to create a building in a space where I teach (essentially, my office). However, I want to be able to make it "go away" without de-rezz when I am not teaching (make it "phantom" and "invisible" to anyone but me).  I have found some scripts and that have chat commands, which are exactly what I am looking for ... but they seem to not be working (unless they work and I just cannot tell they are working because, well, I am the one enacting the script).  I am definitely a noob on the building end and am looking for any guidance or help.  Thank you!