Installing a template

Download the ZIP file containing the menu template you want to use.
Extract it to a skin folder (if you want the menu style available to just a particular skin), your portal root (if you want the menu style available throughout a particular portal) or /DesktopModules/DDRMenu (if you want the menu style available to the whole DNN instance). You should end up with a folder with the name of menu style containing a menudef.xml manifest file plus any supporting files. For example, after adding the Accordion template to a skin the manifest would be at /Portals/0/Skins/MySkin/Accordion/menudef.xml.