this is what i done:
clicked on spot light at the top right hand corner
searched skins
clicked on 'skins-documents' to open up the folder
opened up the folder with the skins in and copied and paste it into the 'skins-document' folder
you can just drag and drop instead of copy and paste if you prefer
Make sure you dont copy in the whole folder, e.g :
i had 'Flex09v1.1.rar' - opened that up and it put 'Flex09v1.1.rar folder' - opened that, then copied 'Flex09' + 'Flex09_r' into the 'skins-documents' folder
hope this helps