Too late mate. You're just about a month and half late.
This was in the events of splitting BTC at the beginning of August. At that time exchanges like bittrex and bitfinex gave account holders who had bitcoins in their accounts the same amount as Bitcoin Cash on a 1:1 basis.

Now you can't do anything. It's over. You can only get it now as any other coin.
Either exchanging btc to it or getting paid in BCH.