These mods will install as new themes on your TikiWiki site.
Alternatively, you install themes by hand from http://themes.tiki.org. See http://tikiwiki.svn.sourceforge.net/viewvc/tikiwiki/mods/trunk/themes/ for the web view of the Subversion mods repository, and http://themes.tiki.org/tiki-directory_browse.php?parent=12 for links to the latest versions of new and maintained themes in the mods repository.
See Styles and Themes for more information.