Make an folder named TorrentLeech in your custom_plugins folder which is is located within your config folder. From CouchPotato goto Settings->About->Directories (second folder is your config folder) for location. Place the init.py and main.py files inside the TorrentLeech folder.
Restart CouchPotato. Then go to Settings->Searcher to configure just like any other provider. If TorrentLeech doesn't appear as an option, refresh your browser using CTRL + F5 as you may be seeing a cached version.
Go to github.com/swordfischer/CouchPotato.TorrentLeech
Code originally from CouchPotato standard providers, slightly modified.