To choose a skin for your site, go to 'Regional Setup > Lang & Email Setup'
and choose which language you want to set the skin for. In the form
that opens, you can the skin from the 'theme' menu. If there are
multiple masterpages in the skin, you can choose one of those too.
If you leave either selection blank, Kartris will use the defaults (which are the skin 'Kartris' and the 'Template.master' template file).
This menu automatically picks up any new folders added to the /Skins folder within a Kartris site. So all you have to do to import or create a new skin is to place the new folder there and then select it from this menu.