https://github.com/Genoil/cpp-ethereum/tree/master/releases and click on the version that you want; once there click "Raw" an it will download. Unzip and go; if you have not used Ethminer before I would suggest this getting started guide https://eth.suprnova.cc/index.php?page=gettingstarted. From there you can take a look at the forums for additional guides on how to tweak the mining.