I have downloaded Stockfish 6 and also I have ChessBase 13 64-bit. I have unzipped to Stockfish how do I combine the two so I can use Stockfish?
Open a game window. On the File ribbon, look for a little UCI written in red just after where it says Remove Kibitzer. Click on that, then in the dialog that pops up click on the button with three dots, and navigate to wherever you have Stockfish on your system. The Author and Name will get filled in automatically. Click on OK, and now Stockfish will appear in the dialog that appears when you click Add Kibitzer.