After you download the archive, extract it and then launch the only executable available within the archive. If Opera is installed on your computer, the software will detect the location of the cache file and then you can browse throw it.
Secondly, if the cache isn't detected, press the folder icon and specify the cache folder manually and browsing will be available through the cache files.
For additional information, use the following link: http://nirsoft.net/utils/opera_cache_view.html
