[otrs] Creating own skin

Hi everybody, I am thinking about changing things on different templates of the system. Now I actually do not want to make/test those on the running skin of the users. So I came up with the idea of cloning the default skin into a dev skin and then change only the dev skin (and use it for my personal settings) Unfortunately I did not find a doc on what I need to do to create a own skin. Any hints? Has anybody done that before? Or is it actually as easy as cloning the "Kernel/Output/HTML/Standard" dir? Felix