To get free CDY, you need to hold Bitcoin Cash before height 512666 (about January 13). 
1.If your BCH is stored in a wallet where you can control private key yourself, you will definitely get free CDY. Just waiting for the wallet developer to provide feature to claim. 
2.If your BCH is stored in the exchange, the exchange will receive free CDY, please pay attention whether the exchange will provide CDY's collection function or not.If the exchange you store BCH does not support CDY, to avoid the loss of assets it is recommended to withdraw BCH to a wallet which you can contral private key or to exchanges that support CDY.